diff --git a/java-overridable/src/com/android/inputmethod/latin/define/ProductionFlags.java b/java-overridable/src/com/android/inputmethod/latin/define/ProductionFlags.java
index 9d7258d..5738ea2 100644
--- a/java-overridable/src/com/android/inputmethod/latin/define/ProductionFlags.java
+++ b/java-overridable/src/com/android/inputmethod/latin/define/ProductionFlags.java
@@ -24,14 +24,6 @@
     public static final boolean IS_HARDWARE_KEYBOARD_SUPPORTED = false;
 
     /**
-     * When true, enable {@link InputMethodService#onUpdateCursorAnchorInfo} callback via
-     * {@link InputConnection#requestUpdateCursorAnchorInfo}. This flag has no effect in API
-     * Level 20 and prior. In general, this callback provides detailed positional information,
-     * even though an explicit support is required by the editor.
-     */
-    public static final boolean ENABLE_CURSOR_ANCHOR_INFO_CALLBACK = true;
-
-    /**
      * Include all suggestions from all dictionaries in {@link SuggestedWords#mRawSuggestions}.
      */
     public static final boolean INCLUDE_RAW_SUGGESTIONS = false;
diff --git a/java/AndroidManifest.xml b/java/AndroidManifest.xml
index 25fa0f9..ee1cef6 100644
--- a/java/AndroidManifest.xml
+++ b/java/AndroidManifest.xml
@@ -89,8 +89,7 @@
 
         <activity android:name=".settings.SettingsActivity"
                 android:theme="@style/platformSettingsTheme"
-                android:label="@string/english_ime_settings"
-                android:uiOptions="splitActionBarWhenNarrow">
+                android:label="@string/english_ime_settings">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
             </intent-filter>
diff --git a/java/res/raw/setup_welcome_image.png b/java/res/raw/setup_welcome_image.png
index 98e7313..b726181 100644
--- a/java/res/raw/setup_welcome_image.png
+++ b/java/res/raw/setup_welcome_image.png
Binary files differ
diff --git a/java/res/raw/setup_welcome_video.mp4 b/java/res/raw/setup_welcome_video.mp4
index 224bf25..09be565 100644
--- a/java/res/raw/setup_welcome_video.mp4
+++ b/java/res/raw/setup_welcome_video.mp4
Binary files differ
diff --git a/java/res/xml/method.xml b/java/res/xml/method.xml
index 8cc6642..77a46f9 100644
--- a/java/res/xml/method.xml
+++ b/java/res/xml/method.xml
@@ -183,6 +183,7 @@
     />
     <!-- TODO: This Bengali (Bangladesh) keyboard is a preliminary layout.
                This isn't based on the final specification. -->
+    <!--
     <subtype android:icon="@drawable/ic_ime_switcher_dark"
             android:label="@string/subtype_generic"
             android:subtypeId="0xa2144b0c"
@@ -191,6 +192,7 @@
             android:imeSubtypeExtraValue="KeyboardLayoutSet=bengali_akkhor,EmojiCapable"
             android:isAsciiCapable="false"
     />
+    -->
     <subtype android:icon="@drawable/ic_ime_switcher_dark"
             android:label="@string/subtype_generic"
             android:subtypeId="0xbff5986c"
@@ -369,6 +371,7 @@
     />
     <!-- TODO: This Hinglish keyboard is a preliminary layout.
                This isn't based on the final specification. -->
+    <!--
     <subtype android:icon="@drawable/ic_ime_switcher_dark"
             android:label="@string/subtype_hi_ZZ"
             android:subtypeId="0x352eb37c"
@@ -377,6 +380,7 @@
             android:imeSubtypeExtraValue="AsciiCapable,KeyboardLayoutSet=qwerty,EmojiCapable"
             android:isAsciiCapable="true"
     />
+    -->
     <subtype android:icon="@drawable/ic_ime_switcher_dark"
             android:label="@string/subtype_generic"
             android:subtypeId="0x35b7526a"
@@ -549,6 +553,7 @@
     />
     <!-- TODO: This Myanmar keyboard is a preliminary layout.
                This isn't based on the final specification. -->
+    <!--
     <subtype android:icon="@drawable/ic_ime_switcher_dark"
             android:label="@string/subtype_generic"
             android:subtypeId="0xea266ea4"
@@ -557,6 +562,7 @@
             android:imeSubtypeExtraValue="KeyboardLayoutSet=myanmar,EmojiCapable,CombiningRules=MyanmarReordering"
             android:isAsciiCapable="false"
     />
+    -->
     <subtype android:icon="@drawable/ic_ime_switcher_dark"
             android:label="@string/subtype_generic"
             android:subtypeId="0x3f12ee14"
@@ -639,6 +645,7 @@
     />
     <!-- TODO: This Sinhala keyboard is a preliminary layout.
                This isn't based on the final specification. -->
+    <!--
     <subtype android:icon="@drawable/ic_ime_switcher_dark"
             android:label="@string/subtype_generic"
             android:subtypeId="0x5c6b3bde"
@@ -647,6 +654,7 @@
             android:imeSubtypeExtraValue="KeyboardLayoutSet=sinhala,EmojiCapable"
             android:isAsciiCapable="false"
     />
+    -->
     <subtype android:icon="@drawable/ic_ime_switcher_dark"
             android:label="@string/subtype_generic"
             android:subtypeId="0x8e94d413"
@@ -673,6 +681,7 @@
     />
     <!-- TODO: This Serbian Latin keyboard is a preliminary layout.
                This isn't based on the final specification. -->
+    <!--
     <subtype android:icon="@drawable/ic_ime_switcher_dark"
             android:label="@string/subtype_sr_ZZ"
             android:subtypeId="0xf4a5569c"
@@ -681,6 +690,7 @@
             android:imeSubtypeExtraValue="KeyboardLayoutSet=serbian_qwertz,AsciiCapable,EmojiCapable"
             android:isAsciiCapable="true"
     />
+    -->
     <subtype android:icon="@drawable/ic_ime_switcher_dark"
             android:label="@string/subtype_generic"
             android:subtypeId="0x48b4ff43"
@@ -706,6 +716,7 @@
             android:isAsciiCapable="false"
     />
     <!-- TODO: Enabling/Disabling ta_LK subtype must be aligned with si_LK subtype. -->
+    <!--
     <subtype android:icon="@drawable/ic_ime_switcher_dark"
             android:label="@string/subtype_generic"
             android:subtypeId="0x6ca12d84"
@@ -714,6 +725,7 @@
             android:imeSubtypeExtraValue="KeyboardLayoutSet=tamil,EmojiCapable"
             android:isAsciiCapable="false"
     />
+    -->
     <subtype android:icon="@drawable/ic_ime_switcher_dark"
             android:label="@string/subtype_generic"
             android:subtypeId="0x785abbd9"
@@ -764,6 +776,7 @@
     />
     <!-- TODO: This Uzbek keyboard is a preliminary layout.
                This isn't based on the final specification. -->
+    <!--
     <subtype android:icon="@drawable/ic_ime_switcher_dark"
             android:label="@string/subtype_generic"
             android:subtypeId="0xad5cf7f6"
@@ -772,6 +785,7 @@
             android:imeSubtypeExtraValue="KeyboardLayoutSet=uzbek,AsciiCapable,EmojiCapable"
             android:isAsciiCapable="true"
     />
+    -->
     <subtype android:icon="@drawable/ic_ime_switcher_dark"
             android:label="@string/subtype_generic"
             android:subtypeId="0x93972eee"
diff --git a/java/src/com/android/inputmethod/keyboard/Key.java b/java/src/com/android/inputmethod/keyboard/Key.java
index bf29b5f..45ce6a8 100644
--- a/java/src/com/android/inputmethod/keyboard/Key.java
+++ b/java/src/com/android/inputmethod/keyboard/Key.java
@@ -278,8 +278,8 @@
 
         mLabelFlags = style.getFlags(keyAttr, R.styleable.Keyboard_Key_keyLabelFlags)
                 | row.getDefaultKeyLabelFlags();
-        final boolean needsToUpperCase = needsToUpperCase(mLabelFlags, params.mId.mElementId);
-        final Locale locale = params.mId.mLocale;
+        final boolean needsToUpcase = needsToUpcase(mLabelFlags, params.mId.mElementId);
+        final Locale localeForUpcasing = params.mId.getLocales()[0];
         int actionFlags = style.getFlags(keyAttr, R.styleable.Keyboard_Key_keyActionFlags);
         String[] moreKeys = style.getStringArray(keyAttr, R.styleable.Keyboard_Key_moreKeys);
 
@@ -321,7 +321,7 @@
             actionFlags |= ACTION_FLAGS_ENABLE_LONG_PRESS;
             mMoreKeys = new MoreKeySpec[moreKeys.length];
             for (int i = 0; i < moreKeys.length; i++) {
-                mMoreKeys[i] = new MoreKeySpec(moreKeys[i], needsToUpperCase, locale);
+                mMoreKeys[i] = new MoreKeySpec(moreKeys[i], needsToUpcase, localeForUpcasing);
             }
         } else {
             mMoreKeys = null;
@@ -342,16 +342,16 @@
             mLabel = new StringBuilder().appendCodePoint(code).toString();
         } else {
             mLabel = StringUtils.toUpperCaseOfStringForLocale(
-                    KeySpecParser.getLabel(keySpec), needsToUpperCase, locale);
+                    KeySpecParser.getLabel(keySpec), needsToUpcase, localeForUpcasing);
         }
         if ((mLabelFlags & LABEL_FLAGS_DISABLE_HINT_LABEL) != 0) {
             mHintLabel = null;
         } else {
             mHintLabel = StringUtils.toUpperCaseOfStringForLocale(style.getString(keyAttr,
-                    R.styleable.Keyboard_Key_keyHintLabel), needsToUpperCase, locale);
+                    R.styleable.Keyboard_Key_keyHintLabel), needsToUpcase, localeForUpcasing);
         }
         String outputText = StringUtils.toUpperCaseOfStringForLocale(
-                KeySpecParser.getOutputText(keySpec), needsToUpperCase, locale);
+                KeySpecParser.getOutputText(keySpec), needsToUpcase, localeForUpcasing);
         // Choose the first letter of the label as primary code if not specified.
         if (code == CODE_UNSPECIFIED && TextUtils.isEmpty(outputText)
                 && !TextUtils.isEmpty(mLabel)) {
@@ -377,12 +377,12 @@
                 mCode = CODE_OUTPUT_TEXT;
             }
         } else {
-            mCode = StringUtils.toUpperCaseOfCodeForLocale(code, needsToUpperCase, locale);
+            mCode = StringUtils.toUpperCaseOfCodeForLocale(code, needsToUpcase, localeForUpcasing);
         }
         final int altCodeInAttr = KeySpecParser.parseCode(
                 style.getString(keyAttr, R.styleable.Keyboard_Key_altCode), CODE_UNSPECIFIED);
         final int altCode = StringUtils.toUpperCaseOfCodeForLocale(
-                altCodeInAttr, needsToUpperCase, locale);
+                altCodeInAttr, needsToUpcase, localeForUpcasing);
         mOptionalAttributes = OptionalAttributes.newInstance(outputText, altCode,
                 disabledIconId, visualInsetsLeft, visualInsetsRight);
         mKeyVisualAttributes = KeyVisualAttributes.newInstance(keyAttr);
@@ -432,7 +432,7 @@
         return (filteredMoreKeys == moreKeys) ? key : new Key(key, filteredMoreKeys);
     }
 
-    private static boolean needsToUpperCase(final int labelFlags, final int keyboardElementId) {
+    private static boolean needsToUpcase(final int labelFlags, final int keyboardElementId) {
         if ((labelFlags & LABEL_FLAGS_PRESERVE_CASE) != 0) return false;
         switch (keyboardElementId) {
         case KeyboardId.ELEMENT_ALPHABET_MANUAL_SHIFTED:
diff --git a/java/src/com/android/inputmethod/keyboard/KeyboardId.java b/java/src/com/android/inputmethod/keyboard/KeyboardId.java
index f9cf353..ab0d633 100644
--- a/java/src/com/android/inputmethod/keyboard/KeyboardId.java
+++ b/java/src/com/android/inputmethod/keyboard/KeyboardId.java
@@ -63,7 +63,6 @@
     public static final int ELEMENT_EMOJI_CATEGORY6 = 16;
 
     public final RichInputMethodSubtype mSubtype;
-    public final Locale mLocale;
     public final int mWidth;
     public final int mHeight;
     public final int mMode;
@@ -79,7 +78,6 @@
 
     public KeyboardId(final int elementId, final KeyboardLayoutSet.Params params) {
         mSubtype = params.mSubtype;
-        mLocale = SubtypeLocaleUtils.getSubtypeLocale(mSubtype);
         mWidth = params.mKeyboardWidth;
         mHeight = params.mKeyboardHeight;
         mMode = params.mMode;
@@ -167,6 +165,10 @@
         return InputTypeUtils.getImeOptionsActionIdFromEditorInfo(mEditorInfo);
     }
 
+    public Locale[] getLocales() {
+        return mSubtype.getLocales();
+    }
+
     @Override
     public boolean equals(final Object other) {
         return other instanceof KeyboardId && equals((KeyboardId) other);
@@ -181,7 +183,8 @@
     public String toString() {
         return String.format(Locale.ROOT, "[%s %s:%s %dx%d %s %s%s%s%s%s%s%s%s%s]",
                 elementIdToName(mElementId),
-                mLocale, mSubtype.getExtraValueOf(KEYBOARD_LAYOUT_SET),
+                Arrays.deepToString(mSubtype.getLocales()),
+                mSubtype.getExtraValueOf(KEYBOARD_LAYOUT_SET),
                 mWidth, mHeight,
                 modeName(mMode),
                 actionName(imeAction()),
diff --git a/java/src/com/android/inputmethod/keyboard/KeyboardSwitcher.java b/java/src/com/android/inputmethod/keyboard/KeyboardSwitcher.java
index 7f2957f..93123d1 100644
--- a/java/src/com/android/inputmethod/keyboard/KeyboardSwitcher.java
+++ b/java/src/com/android/inputmethod/keyboard/KeyboardSwitcher.java
@@ -120,7 +120,9 @@
         mKeyboardLayoutSet = builder.build();
         try {
             mState.onLoadKeyboard(currentAutoCapsState, currentRecapitalizeState);
-            mKeyboardTextsSet.setLocale(mSubtypeSwitcher.getCurrentSubtypeLocale(), mThemeContext);
+            // TODO: revisit this for multi-lingual input
+            mKeyboardTextsSet.setLocale(mSubtypeSwitcher.getCurrentSubtypeLocales()[0],
+                    mThemeContext);
         } catch (KeyboardLayoutSetException e) {
             Log.w(TAG, "loading keyboard failed: " + e.mKeyboardId, e.getCause());
             return;
@@ -161,7 +163,7 @@
                 currentSettingsValues.mKeyPreviewDismissDuration);
         keyboardView.updateShortcutKey(mSubtypeSwitcher.isShortcutImeReady());
         final boolean subtypeChanged = (oldKeyboard == null)
-                || !keyboard.mId.mLocale.equals(oldKeyboard.mId.mLocale);
+                || !keyboard.mId.mSubtype.equals(oldKeyboard.mId.mSubtype);
         final int languageOnSpacebarFormatType = mSubtypeSwitcher.getLanguageOnSpacebarFormatType(
                 keyboard.mId.mSubtype);
         final boolean hasMultipleEnabledIMEsOrSubtypes = RichInputMethodManager.getInstance()
diff --git a/java/src/com/android/inputmethod/keyboard/MainKeyboardView.java b/java/src/com/android/inputmethod/keyboard/MainKeyboardView.java
index cded2cb..ad30b74 100644
--- a/java/src/com/android/inputmethod/keyboard/MainKeyboardView.java
+++ b/java/src/com/android/inputmethod/keyboard/MainKeyboardView.java
@@ -875,6 +875,11 @@
     // Layout language name on spacebar.
     private String layoutLanguageOnSpacebar(final Paint paint,
             final RichInputMethodSubtype subtype, final int width) {
+        if (mLanguageOnSpacebarFormatType == LanguageOnSpacebarHelper.FORMAT_TYPE_MULTIPLE) {
+            // TODO: return an appropriate string
+            return "";
+        }
+
         // Choose appropriate language name to fit into the width.
         if (mLanguageOnSpacebarFormatType == LanguageOnSpacebarHelper.FORMAT_TYPE_FULL_LOCALE) {
             final String fullText = subtype.getFullDisplayName();
diff --git a/java/src/com/android/inputmethod/keyboard/internal/KeyboardBuilder.java b/java/src/com/android/inputmethod/keyboard/internal/KeyboardBuilder.java
index 5038555..f4e010c 100644
--- a/java/src/com/android/inputmethod/keyboard/internal/KeyboardBuilder.java
+++ b/java/src/com/android/inputmethod/keyboard/internal/KeyboardBuilder.java
@@ -45,6 +45,7 @@
 
 import java.io.IOException;
 import java.util.Arrays;
+import java.util.Locale;
 
 /**
  * Keyboard Building helper.
@@ -281,7 +282,8 @@
 
             params.mThemeId = keyboardAttr.getInt(R.styleable.Keyboard_themeId, 0);
             params.mIconsSet.loadIcons(keyboardAttr);
-            params.mTextsSet.setLocale(params.mId.mLocale, mContext);
+            // TODO: this needs to be revisited for multi-lingual input.
+            params.mTextsSet.setLocale(params.mId.getLocales()[0], mContext);
 
             final int resourceId = keyboardAttr.getResourceId(
                     R.styleable.Keyboard_touchPositionCorrectionData, 0);
@@ -672,12 +674,10 @@
                     R.styleable.Keyboard_Case_imeAction, id.imeAction());
             final boolean isIconDefinedMatched = isIconDefined(caseAttr,
                     R.styleable.Keyboard_Case_isIconDefined, mParams.mIconsSet);
-            final boolean localeCodeMatched = matchString(caseAttr,
-                    R.styleable.Keyboard_Case_localeCode, id.mLocale.toString());
-            final boolean languageCodeMatched = matchString(caseAttr,
-                    R.styleable.Keyboard_Case_languageCode, id.mLocale.getLanguage());
-            final boolean countryCodeMatched = matchString(caseAttr,
-                    R.styleable.Keyboard_Case_countryCode, id.mLocale.getCountry());
+            final Locale[] locales = id.getLocales();
+            final boolean localeCodeMatched = matchLocaleCodes(caseAttr, locales);
+            final boolean languageCodeMatched = matchLanguageCodes(caseAttr, locales);
+            final boolean countryCodeMatched = matchCountryCodes(caseAttr, locales);
             final boolean splitLayoutMatched = matchBoolean(caseAttr,
                     R.styleable.Keyboard_Case_isSplitLayout, id.mIsSplitLayout);
             final boolean selected = keyboardLayoutSetMatched && keyboardLayoutSetElementMatched
@@ -733,6 +733,23 @@
         }
     }
 
+    private boolean matchLocaleCodes(TypedArray caseAttr, final Locale[] locales) {
+        // TODO: adujst this for multilingual input
+        return matchString(caseAttr, R.styleable.Keyboard_Case_localeCode, locales[0].toString());
+    }
+
+    private boolean matchLanguageCodes(TypedArray caseAttr, Locale[] locales) {
+        // TODO: adujst this for multilingual input
+        return matchString(caseAttr, R.styleable.Keyboard_Case_languageCode,
+                locales[0].getLanguage());
+    }
+
+    private boolean matchCountryCodes(TypedArray caseAttr, Locale[] locales) {
+        // TODO: adujst this for multilingual input
+        return matchString(caseAttr, R.styleable.Keyboard_Case_countryCode,
+                locales[0].getCountry());
+    }
+
     private static boolean matchInteger(final TypedArray a, final int index, final int value) {
         // If <case> does not have "index" attribute, that means this <case> is wild-card for
         // the attribute.
diff --git a/java/src/com/android/inputmethod/keyboard/internal/LanguageOnSpacebarHelper.java b/java/src/com/android/inputmethod/keyboard/internal/LanguageOnSpacebarHelper.java
index 72ad2bd..21eaed9 100644
--- a/java/src/com/android/inputmethod/keyboard/internal/LanguageOnSpacebarHelper.java
+++ b/java/src/com/android/inputmethod/keyboard/internal/LanguageOnSpacebarHelper.java
@@ -23,6 +23,7 @@
 
 import java.util.Collections;
 import java.util.List;
+import java.util.Locale;
 
 /**
  * This class determines that the language name on the spacebar should be displayed in what format.
@@ -31,6 +32,7 @@
     public static final int FORMAT_TYPE_NONE = 0;
     public static final int FORMAT_TYPE_LANGUAGE_ONLY = 1;
     public static final int FORMAT_TYPE_FULL_LOCALE = 2;
+    public static final int FORMAT_TYPE_MULTIPLE = 3;
 
     private List<InputMethodSubtype> mEnabledSubtypes = Collections.emptyList();
     private boolean mIsSystemLanguageSameAsInputLanguage;
@@ -43,7 +45,11 @@
         if (mEnabledSubtypes.size() < 2 && mIsSystemLanguageSameAsInputLanguage) {
             return FORMAT_TYPE_NONE;
         }
-        final String keyboardLanguage = SubtypeLocaleUtils.getSubtypeLocale(subtype).getLanguage();
+        final Locale[] locales = subtype.getLocales();
+        if (1 < locales.length) {
+            return FORMAT_TYPE_MULTIPLE;
+        }
+        final String keyboardLanguage = locales[0].getLanguage();
         final String keyboardLayout = SubtypeLocaleUtils.getKeyboardLayoutSetName(subtype);
         int sameLanguageAndLayoutCount = 0;
         for (final InputMethodSubtype ims : mEnabledSubtypes) {
diff --git a/java/src/com/android/inputmethod/latin/DictionaryFacilitator.java b/java/src/com/android/inputmethod/latin/DictionaryFacilitator.java
index 1f03172..4a218d5 100644
--- a/java/src/com/android/inputmethod/latin/DictionaryFacilitator.java
+++ b/java/src/com/android/inputmethod/latin/DictionaryFacilitator.java
@@ -416,33 +416,38 @@
     }
 
     @UsedForTesting
-    public void resetDictionariesForTesting(final Context context, final Locale locale,
+    public void resetDictionariesForTesting(final Context context, final Locale[] locales,
             final ArrayList<String> dictionaryTypes, final HashMap<String, File> dictionaryFiles,
             final Map<String, Map<String, String>> additionalDictAttributes) {
         Dictionary mainDictionary = null;
         final Map<String, ExpandableBinaryDictionary> subDicts = new HashMap<>();
 
-        for (final String dictType : dictionaryTypes) {
-            if (dictType.equals(Dictionary.TYPE_MAIN)) {
-                mainDictionary = DictionaryFactory.createMainDictionaryFromManager(context, locale);
-            } else {
-                final File dictFile = dictionaryFiles.get(dictType);
-                final ExpandableBinaryDictionary dict = getSubDict(
-                        dictType, context, locale, dictFile, "" /* dictNamePrefix */);
-                if (additionalDictAttributes.containsKey(dictType)) {
-                    dict.clearAndFlushDictionaryWithAdditionalAttributes(
-                            additionalDictAttributes.get(dictType));
+        final DictionaryGroup[] dictionaryGroups = new DictionaryGroup[locales.length];
+        for (int i = 0; i < locales.length; ++i) {
+            final Locale locale = locales[i];
+            for (final String dictType : dictionaryTypes) {
+                if (dictType.equals(Dictionary.TYPE_MAIN)) {
+                    mainDictionary = DictionaryFactory.createMainDictionaryFromManager(context,
+                            locale);
+                } else {
+                    final File dictFile = dictionaryFiles.get(dictType);
+                    final ExpandableBinaryDictionary dict = getSubDict(
+                            dictType, context, locale, dictFile, "" /* dictNamePrefix */);
+                    if (additionalDictAttributes.containsKey(dictType)) {
+                        dict.clearAndFlushDictionaryWithAdditionalAttributes(
+                                additionalDictAttributes.get(dictType));
+                    }
+                    if (dict == null) {
+                        throw new RuntimeException("Unknown dictionary type: " + dictType);
+                    }
+                    dict.reloadDictionaryIfRequired();
+                    dict.waitAllTasksForTests();
+                    subDicts.put(dictType, dict);
                 }
-                if (dict == null) {
-                    throw new RuntimeException("Unknown dictionary type: " + dictType);
-                }
-                dict.reloadDictionaryIfRequired();
-                dict.waitAllTasksForTests();
-                subDicts.put(dictType, dict);
             }
+            dictionaryGroups[i] = new DictionaryGroup(locale, mainDictionary, subDicts);
         }
-        mDictionaryGroups = new DictionaryGroup[] {
-                new DictionaryGroup(locale, mainDictionary, subDicts) };
+        mDictionaryGroups = dictionaryGroups;
     }
 
     public void closeDictionaries() {
diff --git a/java/src/com/android/inputmethod/latin/LatinIME.java b/java/src/com/android/inputmethod/latin/LatinIME.java
index be2efb2..8e93761 100644
--- a/java/src/com/android/inputmethod/latin/LatinIME.java
+++ b/java/src/com/android/inputmethod/latin/LatinIME.java
@@ -102,7 +102,7 @@
 import java.io.FileDescriptor;
 import java.io.PrintWriter;
 import java.util.ArrayList;
-import java.util.Collections;
+import java.util.Arrays;
 import java.util.List;
 import java.util.Locale;
 import java.util.concurrent.TimeUnit;
@@ -575,18 +575,19 @@
     // Has to be package-visible for unit tests
     @UsedForTesting
     void loadSettings() {
-        final Locale locale = mSubtypeSwitcher.getCurrentSubtypeLocale();
+        final Locale[] locales = mSubtypeSwitcher.getCurrentSubtypeLocales();
         final EditorInfo editorInfo = getCurrentInputEditorInfo();
         final InputAttributes inputAttributes = new InputAttributes(
                 editorInfo, isFullscreenMode(), getPackageName());
-        mSettings.loadSettings(this, locale, inputAttributes);
+        // TODO: pass the array instead
+        mSettings.loadSettings(this, locales[0], inputAttributes);
         final SettingsValues currentSettingsValues = mSettings.getCurrent();
         AudioAndHapticFeedbackManager.getInstance().onSettingsChanged(currentSettingsValues);
         // This method is called on startup and language switch, before the new layout has
         // been displayed. Opening dictionaries never affects responsivity as dictionaries are
         // asynchronously loaded.
         if (!mHandler.hasPendingReopenDictionaries()) {
-            resetDictionaryFacilitatorForLocale(locale);
+            resetDictionaryFacilitatorForLocale(locales);
         }
         mDictionaryFacilitator.updateEnabledSubtypes(mRichImm.getMyEnabledInputMethodSubtypeList(
                 true /* allowsImplicitlySelectedSubtypes */));
@@ -628,35 +629,34 @@
     }
 
     private void resetDictionaryFacilitatorIfNecessary() {
-        final Locale switcherSubtypeLocale = mSubtypeSwitcher.getCurrentSubtypeLocale();
-        if (mDictionaryFacilitator.isForLocales(new Locale[] { switcherSubtypeLocale })) {
+        final Locale[] subtypeSwitcherLocales = mSubtypeSwitcher.getCurrentSubtypeLocales();
+        if (mDictionaryFacilitator.isForLocales(subtypeSwitcherLocales)) {
             return;
         }
-        final String switcherLocaleStr = switcherSubtypeLocale.toString();
-        final Locale subtypeLocale;
-        if (TextUtils.isEmpty(switcherLocaleStr)) {
+        final Locale[] subtypeLocales;
+        if (0 == subtypeSwitcherLocales.length) {
             // This happens in very rare corner cases - for example, immediately after a switch
             // to LatinIME has been requested, about a frame later another switch happens. In this
             // case, we are about to go down but we still don't know it, however the system tells
-            // us there is no current subtype so the locale is the empty string. Take the best
-            // possible guess instead -- it's bound to have no consequences, and we have no way
-            // of knowing anyway.
+            // us there is no current subtype.
             Log.e(TAG, "System is reporting no current subtype.");
-            subtypeLocale = getResources().getConfiguration().locale;
+            subtypeLocales = new Locale[] { getResources().getConfiguration().locale };
         } else {
-            subtypeLocale = switcherSubtypeLocale;
+            subtypeLocales = subtypeSwitcherLocales;
         }
-        resetDictionaryFacilitatorForLocale(subtypeLocale);
+        resetDictionaryFacilitatorForLocale(subtypeLocales);
     }
 
     /**
-     * Reset the facilitator by loading dictionaries for the locale and the current settings values.
+     * Reset the facilitator by loading dictionaries for the locales and the current settings values
      *
-     * @param locale the locale
+     * @param locales the locales
      */
-    // TODO: make sure the current settings always have the right locale, and read from them
-    private void resetDictionaryFacilitatorForLocale(final Locale locale) {
+    // TODO: make sure the current settings always have the right locales, and read from them
+    private void resetDictionaryFacilitatorForLocale(final Locale[] locales) {
         final SettingsValues settingsValues = mSettings.getCurrent();
+        // TODO: pass the array instead
+        final Locale locale = locales[0];
         mDictionaryFacilitator.resetDictionaries(this /* context */, locale,
                 settingsValues.mUseContactsDict, settingsValues.mUsePersonalizedDicts,
                 false /* forceReloadMainDictionary */, this);
@@ -755,12 +755,12 @@
         if (prevExtractEditText == nextExtractEditText) {
             return;
         }
-        if (ProductionFlags.ENABLE_CURSOR_ANCHOR_INFO_CALLBACK && prevExtractEditText != null) {
+        if (prevExtractEditText != null) {
             prevExtractEditText.getViewTreeObserver().removeOnPreDrawListener(
                     mExtractTextViewPreDrawListener);
         }
         mExtractEditText = nextExtractEditText;
-        if (ProductionFlags.ENABLE_CURSOR_ANCHOR_INFO_CALLBACK && mExtractEditText != null) {
+        if (mExtractEditText != null) {
             mExtractEditText.getViewTreeObserver().addOnPreDrawListener(
                     mExtractTextViewPreDrawListener);
         }
@@ -776,8 +776,7 @@
             };
 
     private void onExtractTextViewPreDraw() {
-        if (!ProductionFlags.ENABLE_CURSOR_ANCHOR_INFO_CALLBACK || !isFullscreenMode()
-                || mExtractEditText == null) {
+        if (!isFullscreenMode() || mExtractEditText == null) {
             return;
         }
         final CursorAnchorInfo info = CursorAnchorInfoUtils.getCursorAnchorInfo(mExtractEditText);
@@ -881,7 +880,7 @@
         // Update to a gesture consumer with the current editor and IME state.
         mGestureConsumer = GestureConsumer.newInstance(editorInfo,
                 mInputLogic.getPrivateCommandPerformer(),
-                Collections.singletonList(mSubtypeSwitcher.getCurrentSubtypeLocale()),
+                Arrays.asList(mSubtypeSwitcher.getCurrentSubtypeLocales()),
                 switcher.getKeyboard());
 
         // Forward this event to the accessibility utilities, if enabled.
@@ -1060,7 +1059,7 @@
     // We cannot mark this method as @Override until new SDK becomes publicly available.
     // @Override
     public void onUpdateCursorAnchorInfo(final CursorAnchorInfo info) {
-        if (!ProductionFlags.ENABLE_CURSOR_ANCHOR_INFO_CALLBACK || isFullscreenMode()) {
+        if (isFullscreenMode()) {
             return;
         }
         mInputLogic.onUpdateCursorAnchorInfo(CursorAnchorInfoCompatWrapper.fromObject(info));
@@ -1434,7 +1433,7 @@
     public void onStartBatchInput() {
         mInputLogic.onStartBatchInput(mSettings.getCurrent(), mKeyboardSwitcher, mHandler);
         mGestureConsumer.onGestureStarted(
-                Collections.singletonList(mSubtypeSwitcher.getCurrentSubtypeLocale()),
+                Arrays.asList(mSubtypeSwitcher.getCurrentSubtypeLocales()),
                 mKeyboardSwitcher.getKeyboard());
     }
 
@@ -1558,7 +1557,7 @@
                 // We should clear the contextual strip if there is no suggestion from dictionaries.
                 || noSuggestionsFromDictionaries) {
             mSuggestionStripView.setSuggestions(suggestedWords,
-                    SubtypeLocaleUtils.isRtlLanguage(mSubtypeSwitcher.getCurrentSubtype()));
+                    mSubtypeSwitcher.getCurrentSubtype().isRtlSubtype());
         }
     }
 
diff --git a/java/src/com/android/inputmethod/latin/RichInputMethodSubtype.java b/java/src/com/android/inputmethod/latin/RichInputMethodSubtype.java
index 0b08c48..8d05553 100644
--- a/java/src/com/android/inputmethod/latin/RichInputMethodSubtype.java
+++ b/java/src/com/android/inputmethod/latin/RichInputMethodSubtype.java
@@ -114,10 +114,13 @@
         return "Multi-lingual subtype: " + mSubtype.toString() + ", " + Arrays.toString(mLocales);
     }
 
-    // TODO: remove this method! We can always have several locales. Multi-lingual input will only
-    // be done when this method is gone.
-    public String getLocale() {
-        return mSubtype.getLocale();
+    public Locale[] getLocales() {
+        return mLocales;
+    }
+
+    public boolean isRtlSubtype() {
+        // The subtype is considered RTL if the language of the main subtype is RTL.
+        return SubtypeLocaleUtils.isRtlLanguage(mLocales[0]);
     }
 
     // TODO: remove this method
diff --git a/java/src/com/android/inputmethod/latin/SubtypeSwitcher.java b/java/src/com/android/inputmethod/latin/SubtypeSwitcher.java
index 45d67ff..c339e96 100644
--- a/java/src/com/android/inputmethod/latin/SubtypeSwitcher.java
+++ b/java/src/com/android/inputmethod/latin/SubtypeSwitcher.java
@@ -170,15 +170,21 @@
             Log.w(TAG, "onSubtypeChanged: " + newSubtype.getNameForLogging());
         }
 
-        final Locale newLocale = SubtypeLocaleUtils.getSubtypeLocale(newSubtype);
-        final Locale systemLocale = mResources.getConfiguration().locale;
-        final boolean sameLocale = systemLocale.equals(newLocale);
-        final boolean sameLanguage = systemLocale.getLanguage().equals(newLocale.getLanguage());
-        final boolean implicitlyEnabled = mRichImm
-                .checkIfSubtypeBelongsToThisImeAndImplicitlyEnabled(newSubtype.getRawSubtype());
-        mLanguageOnSpacebarHelper.updateIsSystemLanguageSameAsInputLanguage(
-                sameLocale || (sameLanguage && implicitlyEnabled));
-
+        final Locale[] newLocales = newSubtype.getLocales();
+        if (newLocales.length > 1) {
+            // In multi-locales mode, the system language is never the same as the input language
+            // because there is no single input language.
+            mLanguageOnSpacebarHelper.updateIsSystemLanguageSameAsInputLanguage(false);
+        } else {
+            final Locale newLocale = newLocales[0];
+            final Locale systemLocale = mResources.getConfiguration().locale;
+            final boolean sameLocale = systemLocale.equals(newLocale);
+            final boolean sameLanguage = systemLocale.getLanguage().equals(newLocale.getLanguage());
+            final boolean implicitlyEnabled = mRichImm
+                    .checkIfSubtypeBelongsToThisImeAndImplicitlyEnabled(newSubtype.getRawSubtype());
+            mLanguageOnSpacebarHelper.updateIsSystemLanguageSameAsInputLanguage(
+                    sameLocale || (sameLanguage && implicitlyEnabled));
+        }
         updateShortcutIME();
     }
 
@@ -284,11 +290,11 @@
         sForcedSubtypeForTesting = new RichInputMethodSubtype(subtype);
     }
 
-    public Locale getCurrentSubtypeLocale() {
+    public Locale[] getCurrentSubtypeLocales() {
         if (null != sForcedSubtypeForTesting) {
-            return LocaleUtils.constructLocaleFromString(sForcedSubtypeForTesting.getLocale());
+            return sForcedSubtypeForTesting.getLocales();
         }
-        return SubtypeLocaleUtils.getSubtypeLocale(getCurrentSubtype());
+        return getCurrentSubtype().getLocales();
     }
 
     public RichInputMethodSubtype getCurrentSubtype() {
diff --git a/java/src/com/android/inputmethod/latin/inputlogic/InputLogic.java b/java/src/com/android/inputmethod/latin/inputlogic/InputLogic.java
index 1b1d5e7..f67a9a6 100644
--- a/java/src/com/android/inputmethod/latin/inputlogic/InputLogic.java
+++ b/java/src/com/android/inputmethod/latin/inputlogic/InputLogic.java
@@ -169,14 +169,11 @@
             mInputLogicHandler.reset();
         }
 
-        if (ProductionFlags.ENABLE_CURSOR_ANCHOR_INFO_CALLBACK) {
-            // AcceptTypedWord feature relies on CursorAnchorInfo.
-            if (settingsValues.mShouldShowUiToAcceptTypedWord) {
-                mConnection.requestCursorUpdates(true /* enableMonitor */,
-                        true /* requestImmediateCallback */);
-            }
-            mTextDecorator.reset();
+        if (settingsValues.mShouldShowUiToAcceptTypedWord) {
+            mConnection.requestCursorUpdates(true /* enableMonitor */,
+                    true /* requestImmediateCallback */);
         }
+        mTextDecorator.reset();
     }
 
     /**
diff --git a/java/src/com/android/inputmethod/latin/settings/CustomInputStyleSettingsFragment.java b/java/src/com/android/inputmethod/latin/settings/CustomInputStyleSettingsFragment.java
index 2174f52..c633fc1 100644
--- a/java/src/com/android/inputmethod/latin/settings/CustomInputStyleSettingsFragment.java
+++ b/java/src/com/android/inputmethod/latin/settings/CustomInputStyleSettingsFragment.java
@@ -33,7 +33,6 @@
 import android.support.v4.view.ViewCompat;
 import android.text.TextUtils;
 import android.util.Log;
-import android.util.Pair;
 import android.view.LayoutInflater;
 import android.view.Menu;
 import android.view.MenuInflater;
@@ -80,25 +79,26 @@
             "is_subtype_enabler_notification_dialog_open";
     private static final String KEY_SUBTYPE_FOR_SUBTYPE_ENABLER = "subtype_for_subtype_enabler";
 
-    static final class SubtypeLocaleItem extends Pair<String, String>
-            implements Comparable<SubtypeLocaleItem> {
-        public SubtypeLocaleItem(final String localeString, final String displayName) {
-            super(localeString, displayName);
+    static final class SubtypeLocaleItem implements Comparable<SubtypeLocaleItem> {
+        public final String mLocaleString;
+        private final String mDisplayName;
+
+        public SubtypeLocaleItem(final InputMethodSubtype subtype) {
+            mLocaleString = subtype.getLocale();
+            mDisplayName = SubtypeLocaleUtils.getSubtypeLocaleDisplayNameInSystemLocale(
+                    mLocaleString);
         }
 
-        public SubtypeLocaleItem(final String localeString) {
-            this(localeString,
-                    SubtypeLocaleUtils.getSubtypeLocaleDisplayNameInSystemLocale(localeString));
-        }
-
+        // {@link ArrayAdapter<T>} that hosts the instance of this class needs {@link #toString()}
+        // to get display name.
         @Override
         public String toString() {
-            return second;
+            return mDisplayName;
         }
 
         @Override
         public int compareTo(final SubtypeLocaleItem o) {
-            return first.compareTo(o.first);
+            return mLocaleString.compareTo(o.mLocaleString);
         }
     }
 
@@ -121,32 +121,28 @@
                             SubtypeLocaleUtils.getSubtypeDisplayNameInSystemLocale(subtype)));
                 }
                 if (InputMethodSubtypeCompatUtils.isAsciiCapable(subtype)) {
-                    items.add(createItem(context, subtype.getLocale()));
+                    items.add(new SubtypeLocaleItem(subtype));
                 }
             }
             // TODO: Should filter out already existing combinations of locale and layout.
             addAll(items);
         }
-
-        public static SubtypeLocaleItem createItem(final Context context,
-                final String localeString) {
-            if (localeString.equals(SubtypeLocaleUtils.NO_LANGUAGE)) {
-                final String displayName = context.getString(R.string.subtype_no_language);
-                return new SubtypeLocaleItem(localeString, displayName);
-            }
-            return new SubtypeLocaleItem(localeString);
-        }
     }
 
-    static final class KeyboardLayoutSetItem extends Pair<String, String> {
+    static final class KeyboardLayoutSetItem {
+        public final String mLayoutName;
+        private final String mDisplayName;
+
         public KeyboardLayoutSetItem(final InputMethodSubtype subtype) {
-            super(SubtypeLocaleUtils.getKeyboardLayoutSetName(subtype),
-                    SubtypeLocaleUtils.getKeyboardLayoutSetDisplayName(subtype));
+            mLayoutName = SubtypeLocaleUtils.getKeyboardLayoutSetName(subtype);
+            mDisplayName = SubtypeLocaleUtils.getKeyboardLayoutSetDisplayName(subtype);
         }
 
+        // {@link ArrayAdapter<T>} that hosts the instance of this class needs {@link #toString()}
+        // to get display name.
         @Override
         public String toString() {
-            return second;
+            return mDisplayName;
         }
     }
 
@@ -255,7 +251,6 @@
 
         @Override
         protected void onPrepareDialogBuilder(final AlertDialog.Builder builder) {
-            final Context context = builder.getContext();
             builder.setCancelable(true).setOnCancelListener(this);
             if (isIncomplete()) {
                 builder.setPositiveButton(R.string.add, this)
@@ -264,8 +259,7 @@
                 builder.setPositiveButton(R.string.save, this)
                         .setNeutralButton(android.R.string.cancel, this)
                         .setNegativeButton(R.string.remove, this);
-                final SubtypeLocaleItem localeItem = SubtypeLocaleAdapter.createItem(
-                        context, mSubtype.getLocale());
+                final SubtypeLocaleItem localeItem = new SubtypeLocaleItem(mSubtype);
                 final KeyboardLayoutSetItem layoutItem = new KeyboardLayoutSetItem(mSubtype);
                 setSpinnerPosition(mSubtypeLocaleSpinner, localeItem);
                 setSpinnerPosition(mKeyboardLayoutSetSpinner, layoutItem);
@@ -303,7 +297,7 @@
                         (KeyboardLayoutSetItem) mKeyboardLayoutSetSpinner.getSelectedItem();
                 final InputMethodSubtype subtype =
                         AdditionalSubtypeUtils.createAsciiEmojiCapableAdditionalSubtype(
-                                locale.first, layout.first);
+                                locale.mLocaleString, layout.mLayoutName);
                 setSubtype(subtype);
                 notifyChanged();
                 if (isEditing) {
@@ -469,8 +463,6 @@
                 KEY_IS_SUBTYPE_ENABLER_NOTIFICATION_DIALOG_OPEN)) {
             mSubtypePreferenceKeyForSubtypeEnabler = savedInstanceState.getString(
                     KEY_SUBTYPE_FOR_SUBTYPE_ENABLER);
-            final SubtypePreference subtypePref = (SubtypePreference)findPreference(
-                    mSubtypePreferenceKeyForSubtypeEnabler);
             mSubtypeEnablerNotificationDialog = createDialog();
             mSubtypeEnablerNotificationDialog.show();
         }
diff --git a/java/src/com/android/inputmethod/latin/setup/SetupActivity.java b/java/src/com/android/inputmethod/latin/setup/SetupActivity.java
index b770ea5..7607429 100644
--- a/java/src/com/android/inputmethod/latin/setup/SetupActivity.java
+++ b/java/src/com/android/inputmethod/latin/setup/SetupActivity.java
@@ -17,12 +17,8 @@
 package com.android.inputmethod.latin.setup;
 
 import android.app.Activity;
-import android.content.Context;
 import android.content.Intent;
 import android.os.Bundle;
-import android.provider.Settings;
-import android.view.inputmethod.InputMethodInfo;
-import android.view.inputmethod.InputMethodManager;
 
 public final class SetupActivity extends Activity {
     @Override
diff --git a/java/src/com/android/inputmethod/latin/setup/SetupWizardActivity.java b/java/src/com/android/inputmethod/latin/setup/SetupWizardActivity.java
index e455e53..54562f3 100644
--- a/java/src/com/android/inputmethod/latin/setup/SetupWizardActivity.java
+++ b/java/src/com/android/inputmethod/latin/setup/SetupWizardActivity.java
@@ -46,6 +46,8 @@
 public final class SetupWizardActivity extends Activity implements View.OnClickListener {
     static final String TAG = SetupWizardActivity.class.getSimpleName();
 
+    // For debugging purpose.
+    private static final boolean FORCE_TO_SHOW_WELCOME_SCREEN = false;
     private static final boolean ENABLE_WELCOME_VIDEO = true;
 
     private InputMethodManager mImm;
@@ -304,6 +306,9 @@
 
     private int determineSetupStepNumber() {
         mHandler.cancelPollingImeSettings();
+        if (FORCE_TO_SHOW_WELCOME_SCREEN) {
+            return STEP_1;
+        }
         if (!UncachedInputMethodManagerUtils.isThisImeEnabled(this, mImm)) {
             return STEP_1;
         }
diff --git a/java/src/com/android/inputmethod/latin/utils/SubtypeLocaleUtils.java b/java/src/com/android/inputmethod/latin/utils/SubtypeLocaleUtils.java
index 5a7f766..61661cd 100644
--- a/java/src/com/android/inputmethod/latin/utils/SubtypeLocaleUtils.java
+++ b/java/src/com/android/inputmethod/latin/utils/SubtypeLocaleUtils.java
@@ -293,13 +293,6 @@
         return LocaleUtils.constructLocaleFromString(localeString);
     }
 
-    // TODO: remove this. When RichInputMethodSubtype#getLocale is removed we can do away with this
-    // method at the same time.
-    public static Locale getSubtypeLocale(final RichInputMethodSubtype subtype) {
-        final String localeString = subtype.getLocale();
-        return LocaleUtils.constructLocaleFromString(localeString);
-    }
-
     public static String getKeyboardLayoutSetDisplayName(final InputMethodSubtype subtype) {
         final String layoutName = getKeyboardLayoutSetName(subtype);
         return getKeyboardLayoutSetDisplayName(layoutName);
@@ -348,10 +341,6 @@
         return Arrays.binarySearch(SORTED_RTL_LANGUAGES, language) >= 0;
     }
 
-    public static boolean isRtlLanguage(final RichInputMethodSubtype subtype) {
-        return isRtlLanguage(getSubtypeLocale(subtype));
-    }
-
     public static String getCombiningRulesExtraValue(final InputMethodSubtype subtype) {
         return subtype.getExtraValueOf(Constants.Subtype.ExtraValue.COMBINING_RULES);
     }
diff --git a/native/jni/com_android_inputmethod_latin_BinaryDictionary.cpp b/native/jni/com_android_inputmethod_latin_BinaryDictionary.cpp
index 365217a..76c7fdd 100644
--- a/native/jni/com_android_inputmethod_latin_BinaryDictionary.cpp
+++ b/native/jni/com_android_inputmethod_latin_BinaryDictionary.cpp
@@ -252,6 +252,9 @@
     } else {
         dictionary->getPredictions(&prevWordsInfo, &suggestionResults);
     }
+    if (DEBUG_DICT) {
+        suggestionResults.dumpSuggestions();
+    }
     suggestionResults.outputSuggestions(env, outSuggestionCount, outCodePointsArray,
             outScoresArray, outSpaceIndicesArray, outTypesArray,
             outAutoCommitFirstWordConfidenceArray, inOutWeightOfLangModelVsSpatialModel);
diff --git a/native/jni/src/defines.h b/native/jni/src/defines.h
index e55c9eb..8851185 100644
--- a/native/jni/src/defines.h
+++ b/native/jni/src/defines.h
@@ -119,7 +119,7 @@
         const int probability) {
     static char charBuf[50];
     const int N = intArrayToCharArray(word, length, charBuf, NELEMS(charBuf));
-    if (N > 1) {
+    if (N > 0) {
         AKLOGI("%2d [ %s ] (%d)", rank, charBuf, probability);
     }
 }
diff --git a/native/jni/src/suggest/core/dictionary/dictionary.cpp b/native/jni/src/suggest/core/dictionary/dictionary.cpp
index 8d3f8a9..7a69d3c 100644
--- a/native/jni/src/suggest/core/dictionary/dictionary.cpp
+++ b/native/jni/src/suggest/core/dictionary/dictionary.cpp
@@ -55,9 +55,6 @@
     suggest->getSuggestions(proximityInfo, traverseSession, xcoordinates,
             ycoordinates, times, pointerIds, inputCodePoints, inputSize,
             weightOfLangModelVsSpatialModel, outSuggestionResults);
-    if (DEBUG_DICT) {
-        outSuggestionResults->dumpSuggestions();
-    }
 }
 
 Dictionary::NgramListenerForPrediction::NgramListenerForPrediction(
diff --git a/native/jni/src/suggest/policyimpl/dictionary/header/header_policy.cpp b/native/jni/src/suggest/policyimpl/dictionary/header/header_policy.cpp
index 6ed65d9..4c4dfc5 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/header/header_policy.cpp
+++ b/native/jni/src/suggest/policyimpl/dictionary/header/header_policy.cpp
@@ -35,23 +35,15 @@
 // count.
 const char *const HeaderPolicy::HAS_HISTORICAL_INFO_KEY = "HAS_HISTORICAL_INFO";
 const char *const HeaderPolicy::LOCALE_KEY = "locale"; // match Java declaration
-const char *const HeaderPolicy::FORGETTING_CURVE_OCCURRENCES_TO_LEVEL_UP_KEY =
-        "FORGETTING_CURVE_OCCURRENCES_TO_LEVEL_UP";
 const char *const HeaderPolicy::FORGETTING_CURVE_PROBABILITY_VALUES_TABLE_ID_KEY =
         "FORGETTING_CURVE_PROBABILITY_VALUES_TABLE_ID";
-const char *const HeaderPolicy::FORGETTING_CURVE_DURATION_TO_LEVEL_DOWN_IN_SECONDS_KEY =
-        "FORGETTING_CURVE_DURATION_TO_LEVEL_DOWN_IN_SECONDS";
 
 const char *const HeaderPolicy::MAX_UNIGRAM_COUNT_KEY = "MAX_UNIGRAM_COUNT";
 const char *const HeaderPolicy::MAX_BIGRAM_COUNT_KEY = "MAX_BIGRAM_COUNT";
 
 const int HeaderPolicy::DEFAULT_MULTIPLE_WORDS_DEMOTION_RATE = 100;
 const float HeaderPolicy::MULTIPLE_WORD_COST_MULTIPLIER_SCALE = 100.0f;
-const int HeaderPolicy::DEFAULT_FORGETTING_CURVE_OCCURRENCES_TO_LEVEL_UP = 2;
 const int HeaderPolicy::DEFAULT_FORGETTING_CURVE_PROBABILITY_VALUES_TABLE_ID = 3;
-// 30 days
-const int HeaderPolicy::DEFAULT_FORGETTING_CURVE_DURATION_TO_LEVEL_DOWN_IN_SECONDS =
-        30 * 24 * 60 * 60;
 
 const int HeaderPolicy::DEFAULT_MAX_UNIGRAM_COUNT = 10000;
 const int HeaderPolicy::DEFAULT_MAX_BIGRAM_COUNT = 10000;
diff --git a/native/jni/src/suggest/policyimpl/dictionary/header/header_policy.h b/native/jni/src/suggest/policyimpl/dictionary/header/header_policy.h
index daf40d4..bc8eade 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/header/header_policy.h
+++ b/native/jni/src/suggest/policyimpl/dictionary/header/header_policy.h
@@ -53,15 +53,9 @@
                       EXTENDED_REGION_SIZE_KEY, 0 /* defaultValue */)),
               mHasHistoricalInfoOfWords(HeaderReadWriteUtils::readBoolAttributeValue(
                       &mAttributeMap, HAS_HISTORICAL_INFO_KEY, false /* defaultValue */)),
-              mForgettingCurveOccurrencesToLevelUp(HeaderReadWriteUtils::readIntAttributeValue(
-                      &mAttributeMap, FORGETTING_CURVE_OCCURRENCES_TO_LEVEL_UP_KEY,
-                      DEFAULT_FORGETTING_CURVE_OCCURRENCES_TO_LEVEL_UP)),
               mForgettingCurveProbabilityValuesTableId(HeaderReadWriteUtils::readIntAttributeValue(
                       &mAttributeMap, FORGETTING_CURVE_PROBABILITY_VALUES_TABLE_ID_KEY,
                       DEFAULT_FORGETTING_CURVE_PROBABILITY_VALUES_TABLE_ID)),
-              mForgettingCurveDurationToLevelDown(HeaderReadWriteUtils::readIntAttributeValue(
-                      &mAttributeMap, FORGETTING_CURVE_DURATION_TO_LEVEL_DOWN_IN_SECONDS_KEY,
-                      DEFAULT_FORGETTING_CURVE_DURATION_TO_LEVEL_DOWN_IN_SECONDS)),
               mMaxUnigramCount(HeaderReadWriteUtils::readIntAttributeValue(
                       &mAttributeMap, MAX_UNIGRAM_COUNT_KEY, DEFAULT_MAX_UNIGRAM_COUNT)),
               mMaxBigramCount(HeaderReadWriteUtils::readIntAttributeValue(
@@ -86,15 +80,9 @@
               mUnigramCount(0), mBigramCount(0), mExtendedRegionSize(0),
               mHasHistoricalInfoOfWords(HeaderReadWriteUtils::readBoolAttributeValue(
                       &mAttributeMap, HAS_HISTORICAL_INFO_KEY, false /* defaultValue */)),
-              mForgettingCurveOccurrencesToLevelUp(HeaderReadWriteUtils::readIntAttributeValue(
-                      &mAttributeMap, FORGETTING_CURVE_OCCURRENCES_TO_LEVEL_UP_KEY,
-                      DEFAULT_FORGETTING_CURVE_OCCURRENCES_TO_LEVEL_UP)),
               mForgettingCurveProbabilityValuesTableId(HeaderReadWriteUtils::readIntAttributeValue(
                       &mAttributeMap, FORGETTING_CURVE_PROBABILITY_VALUES_TABLE_ID_KEY,
                       DEFAULT_FORGETTING_CURVE_PROBABILITY_VALUES_TABLE_ID)),
-              mForgettingCurveDurationToLevelDown(HeaderReadWriteUtils::readIntAttributeValue(
-                      &mAttributeMap, FORGETTING_CURVE_DURATION_TO_LEVEL_DOWN_IN_SECONDS_KEY,
-                      DEFAULT_FORGETTING_CURVE_DURATION_TO_LEVEL_DOWN_IN_SECONDS)),
               mMaxUnigramCount(HeaderReadWriteUtils::readIntAttributeValue(
                       &mAttributeMap, MAX_UNIGRAM_COUNT_KEY, DEFAULT_MAX_UNIGRAM_COUNT)),
               mMaxBigramCount(HeaderReadWriteUtils::readIntAttributeValue(
@@ -113,12 +101,8 @@
               mUnigramCount(headerPolicy->mUnigramCount), mBigramCount(headerPolicy->mBigramCount),
               mExtendedRegionSize(headerPolicy->mExtendedRegionSize),
               mHasHistoricalInfoOfWords(headerPolicy->mHasHistoricalInfoOfWords),
-              mForgettingCurveOccurrencesToLevelUp(
-                      headerPolicy->mForgettingCurveOccurrencesToLevelUp),
               mForgettingCurveProbabilityValuesTableId(
                       headerPolicy->mForgettingCurveProbabilityValuesTableId),
-              mForgettingCurveDurationToLevelDown(
-                      headerPolicy->mForgettingCurveDurationToLevelDown),
               mMaxUnigramCount(headerPolicy->mMaxUnigramCount),
               mMaxBigramCount(headerPolicy->mMaxBigramCount),
               mCodePointTable(headerPolicy->mCodePointTable) {}
@@ -130,8 +114,7 @@
               mRequiresGermanUmlautProcessing(false), mIsDecayingDict(false),
               mDate(0), mLastDecayedTime(0), mUnigramCount(0), mBigramCount(0),
               mExtendedRegionSize(0), mHasHistoricalInfoOfWords(false),
-              mForgettingCurveOccurrencesToLevelUp(0), mForgettingCurveProbabilityValuesTableId(0),
-              mForgettingCurveDurationToLevelDown(0), mMaxUnigramCount(0), mMaxBigramCount(0),
+              mForgettingCurveProbabilityValuesTableId(0), mMaxUnigramCount(0), mMaxBigramCount(0),
               mCodePointTable(nullptr) {}
 
     ~HeaderPolicy() {}
@@ -217,18 +200,10 @@
         return &mAttributeMap;
     }
 
-    AK_FORCE_INLINE int getForgettingCurveOccurrencesToLevelUp() const {
-        return mForgettingCurveOccurrencesToLevelUp;
-    }
-
     AK_FORCE_INLINE int getForgettingCurveProbabilityValuesTableId() const {
         return mForgettingCurveProbabilityValuesTableId;
     }
 
-    AK_FORCE_INLINE int getForgettingCurveDurationToLevelDown() const {
-        return mForgettingCurveDurationToLevelDown;
-    }
-
     AK_FORCE_INLINE int getMaxUnigramCount() const {
         return mMaxUnigramCount;
     }
@@ -280,9 +255,7 @@
     static const char *const MAX_BIGRAM_COUNT_KEY;
     static const int DEFAULT_MULTIPLE_WORDS_DEMOTION_RATE;
     static const float MULTIPLE_WORD_COST_MULTIPLIER_SCALE;
-    static const int DEFAULT_FORGETTING_CURVE_OCCURRENCES_TO_LEVEL_UP;
     static const int DEFAULT_FORGETTING_CURVE_PROBABILITY_VALUES_TABLE_ID;
-    static const int DEFAULT_FORGETTING_CURVE_DURATION_TO_LEVEL_DOWN_IN_SECONDS;
     static const int DEFAULT_MAX_UNIGRAM_COUNT;
     static const int DEFAULT_MAX_BIGRAM_COUNT;
 
@@ -300,9 +273,7 @@
     const int mBigramCount;
     const int mExtendedRegionSize;
     const bool mHasHistoricalInfoOfWords;
-    const int mForgettingCurveOccurrencesToLevelUp;
     const int mForgettingCurveProbabilityValuesTableId;
-    const int mForgettingCurveDurationToLevelDown;
     const int mMaxUnigramCount;
     const int mMaxBigramCount;
     const int *const mCodePointTable;
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_policy.cpp b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_policy.cpp
index 11f7b30..36eafa1 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_policy.cpp
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_policy.cpp
@@ -146,18 +146,15 @@
 
 int Ver4PatriciaTriePolicy::getProbability(const int unigramProbability,
         const int bigramProbability) const {
-    if (mHeaderPolicy->isDecayingDict()) {
-        // Both probabilities are encoded. Decode them and get probability.
-        return ForgettingCurveUtils::getProbability(unigramProbability, bigramProbability);
-    } else {
-        if (unigramProbability == NOT_A_PROBABILITY) {
-            return NOT_A_PROBABILITY;
-        } else if (bigramProbability == NOT_A_PROBABILITY) {
-            return ProbabilityUtils::backoff(unigramProbability);
-        } else {
-            return bigramProbability;
-        }
+    // In the v4 format, bigramProbability is a conditional probability.
+    const int bigramConditionalProbability = bigramProbability;
+    if (unigramProbability == NOT_A_PROBABILITY) {
+        return NOT_A_PROBABILITY;
     }
+    if (bigramConditionalProbability == NOT_A_PROBABILITY) {
+        return ProbabilityUtils::backoff(unigramProbability);
+    }
+    return bigramConditionalProbability;
 }
 
 int Ver4PatriciaTriePolicy::getProbabilityOfWord(const WordIdArrayView prevWordIds,
@@ -170,37 +167,66 @@
     if (ptNodeParams.isDeleted() || ptNodeParams.isBlacklisted() || ptNodeParams.isNotAWord()) {
         return NOT_A_PROBABILITY;
     }
-    if (!prevWordIds.empty()) {
-        const int bigramsPosition = getBigramsPositionOfPtNode(
-                getTerminalPtNodePosFromWordId(prevWordIds[0]));
-        BinaryDictionaryBigramsIterator bigramsIt(&mBigramPolicy, bigramsPosition);
-        while (bigramsIt.hasNext()) {
-            bigramsIt.next();
-            if (bigramsIt.getBigramPos() == ptNodePos
-                    && bigramsIt.getProbability() != NOT_A_PROBABILITY) {
-                return getProbability(ptNodeParams.getProbability(), bigramsIt.getProbability());
-            }
-        }
+    if (prevWordIds.empty()) {
+        return getProbability(ptNodeParams.getProbability(), NOT_A_PROBABILITY);
+    }
+    if (prevWordIds[0] == NOT_A_WORD_ID) {
         return NOT_A_PROBABILITY;
     }
-    return getProbability(ptNodeParams.getProbability(), NOT_A_PROBABILITY);
+    const PtNodeParams prevWordPtNodeParams =
+            mNodeReader.fetchPtNodeParamsInBufferFromPtNodePos(prevWordIds[0]);
+    if (prevWordPtNodeParams.isDeleted()) {
+        return getProbability(ptNodeParams.getProbability(), NOT_A_PROBABILITY);
+    }
+    const int bigramsPosition = mBuffers->getBigramDictContent()->getBigramListHeadPos(
+            prevWordPtNodeParams.getTerminalId());
+    BinaryDictionaryBigramsIterator bigramsIt(&mBigramPolicy, bigramsPosition);
+    while (bigramsIt.hasNext()) {
+        bigramsIt.next();
+        if (bigramsIt.getBigramPos() == ptNodePos
+                && bigramsIt.getProbability() != NOT_A_PROBABILITY) {
+            const int bigramConditionalProbability = getBigramConditionalProbability(
+                    prevWordPtNodeParams.getProbability(), bigramsIt.getProbability());
+            return getProbability(ptNodeParams.getProbability(), bigramConditionalProbability);
+        }
+    }
+    return NOT_A_PROBABILITY;
 }
 
 void Ver4PatriciaTriePolicy::iterateNgramEntries(const WordIdArrayView prevWordIds,
         NgramListener *const listener) const {
-    if (prevWordIds.empty()) {
+    if (prevWordIds.firstOrDefault(NOT_A_DICT_POS) == NOT_A_DICT_POS) {
         return;
     }
-    const int bigramsPosition = getBigramsPositionOfPtNode(
-            getTerminalPtNodePosFromWordId(prevWordIds[0]));
+    const PtNodeParams prevWordPtNodeParams =
+            mNodeReader.fetchPtNodeParamsInBufferFromPtNodePos(prevWordIds[0]);
+    if (prevWordPtNodeParams.isDeleted()) {
+        return;
+    }
+    const int bigramsPosition = mBuffers->getBigramDictContent()->getBigramListHeadPos(
+            prevWordPtNodeParams.getTerminalId());
     BinaryDictionaryBigramsIterator bigramsIt(&mBigramPolicy, bigramsPosition);
     while (bigramsIt.hasNext()) {
         bigramsIt.next();
-        listener->onVisitEntry(bigramsIt.getProbability(),
+        const int bigramConditionalProbability = getBigramConditionalProbability(
+                prevWordPtNodeParams.getProbability(), bigramsIt.getProbability());
+        listener->onVisitEntry(bigramConditionalProbability,
                 getWordIdFromTerminalPtNodePos(bigramsIt.getBigramPos()));
     }
 }
 
+int Ver4PatriciaTriePolicy::getBigramConditionalProbability(const int prevWordUnigramProbability,
+        const int bigramProbability) const {
+    if (mHeaderPolicy->hasHistoricalInfoOfWords()) {
+        // Calculate conditional probability.
+        return std::min(MAX_PROBABILITY - prevWordUnigramProbability + bigramProbability,
+                MAX_PROBABILITY);
+    } else {
+        // bigramProbability is a conditional probability.
+        return bigramProbability;
+    }
+}
+
 BinaryDictionaryShortcutIterator Ver4PatriciaTriePolicy::getShortcutIterator(
         const int wordId) const {
     const int shortcutPos = getShortcutPositionOfPtNode(getTerminalPtNodePosFromWordId(wordId));
@@ -428,7 +454,10 @@
         AKLOGE("Cannot update unigarm entry in updateCounter().");
         return false;
     }
-    const NgramProperty ngramProperty(wordCodePoints.toVector(), probability, historicalInfo);
+    const int probabilityForNgram = prevWordsInfo->isNthPrevWordBeginningOfSentence(1 /* n */)
+            ? NOT_A_PROBABILITY : probability;
+    const NgramProperty ngramProperty(wordCodePoints.toVector(), probabilityForNgram,
+            historicalInfo);
     if (!addNgramEntry(prevWordsInfo, &ngramProperty)) {
         AKLOGE("Cannot update unigarm entry in updateCounter().");
         return false;
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_policy.h b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_policy.h
index 995d776..b82563e 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_policy.h
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_policy.h
@@ -174,6 +174,8 @@
     int getTerminalPtNodePosFromWordId(const int wordId) const;
     const WordAttributes getWordAttributes(const int probability,
             const PtNodeParams &ptNodeParams) const;
+    int getBigramConditionalProbability(const int prevWordUnigramProbability,
+            const int bigramProbability) const;
 };
 } // namespace v402
 } // namespace backward
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_policy.cpp b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_policy.cpp
index 41b109f..036197c 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_policy.cpp
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_policy.cpp
@@ -378,7 +378,10 @@
         AKLOGE("Cannot update unigarm entry in updateCounter().");
         return false;
     }
-    const NgramProperty ngramProperty(wordCodePoints.toVector(), probability, historicalInfo);
+    const int probabilityForNgram = prevWordsInfo->isNthPrevWordBeginningOfSentence(1 /* n */)
+            ? NOT_A_PROBABILITY : probability;
+    const NgramProperty ngramProperty(wordCodePoints.toVector(), probabilityForNgram,
+            historicalInfo);
     for (size_t i = 1; i <= prevWordsInfo->getPrevWordCount(); ++i) {
         const PrevWordsInfo trimmedPrevWordsInfo(prevWordsInfo->getTrimmedPrevWordsInfo(i));
         if (!addNgramEntry(&trimmedPrevWordsInfo, &ngramProperty)) {
diff --git a/native/jni/src/suggest/policyimpl/dictionary/utils/forgetting_curve_utils.cpp b/native/jni/src/suggest/policyimpl/dictionary/utils/forgetting_curve_utils.cpp
index af4bc18..e5ef2ab 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/utils/forgetting_curve_utils.cpp
+++ b/native/jni/src/suggest/policyimpl/dictionary/utils/forgetting_curve_utils.cpp
@@ -29,10 +29,14 @@
 const int ForgettingCurveUtils::MULTIPLIER_TWO_IN_PROBABILITY_SCALE = 8;
 const int ForgettingCurveUtils::DECAY_INTERVAL_SECONDS = 2 * 60 * 60;
 
-const int ForgettingCurveUtils::MAX_LEVEL = 3;
-const int ForgettingCurveUtils::MIN_VISIBLE_LEVEL = 1;
-const int ForgettingCurveUtils::MAX_ELAPSED_TIME_STEP_COUNT = 15;
-const int ForgettingCurveUtils::DISCARD_LEVEL_ZERO_ENTRY_TIME_STEP_COUNT_THRESHOLD = 14;
+const int ForgettingCurveUtils::MAX_LEVEL = 15;
+const int ForgettingCurveUtils::MIN_VISIBLE_LEVEL = 2;
+const int ForgettingCurveUtils::MAX_ELAPSED_TIME_STEP_COUNT = 31;
+const int ForgettingCurveUtils::DISCARD_LEVEL_ZERO_ENTRY_TIME_STEP_COUNT_THRESHOLD = 30;
+const int ForgettingCurveUtils::OCCURRENCES_TO_RAISE_THE_LEVEL = 1;
+// TODO: Evaluate whether this should be 7.5 days.
+// 15 days
+const int ForgettingCurveUtils::DURATION_TO_LOWER_THE_LEVEL_IN_SECONDS = 15 * 24 * 60 * 60;
 
 const float ForgettingCurveUtils::UNIGRAM_COUNT_HARD_LIMIT_WEIGHT = 1.2;
 const float ForgettingCurveUtils::BIGRAM_COUNT_HARD_LIMIT_WEIGHT = 1.2;
@@ -54,19 +58,23 @@
             || (originalHistoricalInfo->getLevel() == newHistoricalInfo->getLevel()
                     && originalHistoricalInfo->getCount() < newHistoricalInfo->getCount())) {
         // Initial information.
+        int count = newHistoricalInfo->getCount();
+        if (count >= OCCURRENCES_TO_RAISE_THE_LEVEL) {
+            const int level = clampToValidLevelRange(newHistoricalInfo->getLevel() + 1);
+            return HistoricalInfo(timestamp, level, 0 /* count */);
+        }
         const int level = clampToValidLevelRange(newHistoricalInfo->getLevel());
-        const int count = clampToValidCountRange(newHistoricalInfo->getCount(), headerPolicy);
-        return HistoricalInfo(timestamp, level, count);
+        return HistoricalInfo(timestamp, level, clampToValidCountRange(count, headerPolicy));
     } else {
         const int updatedCount = originalHistoricalInfo->getCount() + 1;
-        if (updatedCount >= headerPolicy->getForgettingCurveOccurrencesToLevelUp()) {
+        if (updatedCount >= OCCURRENCES_TO_RAISE_THE_LEVEL) {
             // The count exceeds the max value the level can be incremented.
             if (originalHistoricalInfo->getLevel() >= MAX_LEVEL) {
                 // The level is already max.
                 return HistoricalInfo(timestamp,
                         originalHistoricalInfo->getLevel(), originalHistoricalInfo->getCount());
             } else {
-                // Level up.
+                // Raise the level.
                 return HistoricalInfo(timestamp,
                         originalHistoricalInfo->getLevel() + 1, 0 /* count */);
             }
@@ -79,31 +87,18 @@
 /* static */ int ForgettingCurveUtils::decodeProbability(
         const HistoricalInfo *const historicalInfo, const HeaderPolicy *const headerPolicy) {
     const int elapsedTimeStepCount = getElapsedTimeStepCount(historicalInfo->getTimestamp(),
-            headerPolicy->getForgettingCurveDurationToLevelDown());
+            DURATION_TO_LOWER_THE_LEVEL_IN_SECONDS);
     return sProbabilityTable.getProbability(
             headerPolicy->getForgettingCurveProbabilityValuesTableId(),
             clampToValidLevelRange(historicalInfo->getLevel()),
             clampToValidTimeStepCountRange(elapsedTimeStepCount));
 }
 
-/* static */ int ForgettingCurveUtils::getProbability(const int unigramProbability,
-        const int bigramProbability) {
-    if (unigramProbability == NOT_A_PROBABILITY) {
-        return NOT_A_PROBABILITY;
-    } else if (bigramProbability == NOT_A_PROBABILITY) {
-        return std::min(backoff(unigramProbability), MAX_PROBABILITY);
-    } else {
-        // TODO: Investigate better way to handle bigram probability.
-        return std::min(std::max(unigramProbability,
-                bigramProbability + MULTIPLIER_TWO_IN_PROBABILITY_SCALE), MAX_PROBABILITY);
-    }
-}
-
 /* static */ bool ForgettingCurveUtils::needsToKeep(const HistoricalInfo *const historicalInfo,
         const HeaderPolicy *const headerPolicy) {
     return historicalInfo->getLevel() > 0
             || getElapsedTimeStepCount(historicalInfo->getTimestamp(),
-                    headerPolicy->getForgettingCurveDurationToLevelDown())
+                    DURATION_TO_LOWER_THE_LEVEL_IN_SECONDS)
                             < DISCARD_LEVEL_ZERO_ENTRY_TIME_STEP_COUNT_THRESHOLD;
 }
 
@@ -113,14 +108,14 @@
     if (originalHistoricalInfo->getTimestamp() == NOT_A_TIMESTAMP) {
         return HistoricalInfo();
     }
-    const int durationToLevelDownInSeconds = headerPolicy->getForgettingCurveDurationToLevelDown();
+    const int durationToLevelDownInSeconds = DURATION_TO_LOWER_THE_LEVEL_IN_SECONDS;
     const int elapsedTimeStep = getElapsedTimeStepCount(
             originalHistoricalInfo->getTimestamp(), durationToLevelDownInSeconds);
     if (elapsedTimeStep <= MAX_ELAPSED_TIME_STEP_COUNT) {
         // No need to update historical info.
         return *originalHistoricalInfo;
     }
-    // Level down.
+    // Lower the level.
     const int maxLevelDownAmonut = elapsedTimeStep / (MAX_ELAPSED_TIME_STEP_COUNT + 1);
     const int levelDownAmount = (maxLevelDownAmonut >= originalHistoricalInfo->getLevel()) ?
             originalHistoricalInfo->getLevel() : maxLevelDownAmonut;
@@ -170,7 +165,7 @@
 
 /* static */ int ForgettingCurveUtils::clampToValidCountRange(const int count,
         const HeaderPolicy *const headerPolicy) {
-    return std::min(std::max(count, 0), headerPolicy->getForgettingCurveOccurrencesToLevelUp() - 1);
+    return std::min(std::max(count, 0), OCCURRENCES_TO_RAISE_THE_LEVEL - 1);
 }
 
 /* static */ int ForgettingCurveUtils::clampToValidLevelRange(const int level) {
@@ -187,9 +182,9 @@
 const int ForgettingCurveUtils::ProbabilityTable::STRONG_PROBABILITY_TABLE_ID = 2;
 const int ForgettingCurveUtils::ProbabilityTable::AGGRESSIVE_PROBABILITY_TABLE_ID = 3;
 const int ForgettingCurveUtils::ProbabilityTable::WEAK_MAX_PROBABILITY = 127;
-const int ForgettingCurveUtils::ProbabilityTable::MODEST_BASE_PROBABILITY = 32;
-const int ForgettingCurveUtils::ProbabilityTable::STRONG_BASE_PROBABILITY = 35;
-const int ForgettingCurveUtils::ProbabilityTable::AGGRESSIVE_BASE_PROBABILITY = 40;
+const int ForgettingCurveUtils::ProbabilityTable::MODEST_BASE_PROBABILITY = 8;
+const int ForgettingCurveUtils::ProbabilityTable::STRONG_BASE_PROBABILITY = 9;
+const int ForgettingCurveUtils::ProbabilityTable::AGGRESSIVE_BASE_PROBABILITY = 10;
 
 
 ForgettingCurveUtils::ProbabilityTable::ProbabilityTable() : mTables() {
@@ -202,7 +197,7 @@
             const float endProbability = getBaseProbabilityForLevel(tableId, level - 1);
             for (int timeStepCount = 0; timeStepCount <= MAX_ELAPSED_TIME_STEP_COUNT;
                     ++timeStepCount) {
-                if (level == 0) {
+                if (level < MIN_VISIBLE_LEVEL) {
                     mTables[tableId][level][timeStepCount] = NOT_A_PROBABILITY;
                     continue;
                 }
diff --git a/native/jni/src/suggest/policyimpl/dictionary/utils/forgetting_curve_utils.h b/native/jni/src/suggest/policyimpl/dictionary/utils/forgetting_curve_utils.h
index 10abb40..ccbc4a9 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/utils/forgetting_curve_utils.h
+++ b/native/jni/src/suggest/policyimpl/dictionary/utils/forgetting_curve_utils.h
@@ -39,9 +39,6 @@
     static int decodeProbability(const HistoricalInfo *const historicalInfo,
             const HeaderPolicy *const headerPolicy);
 
-    static int getProbability(const int encodedUnigramProbability,
-            const int encodedBigramProbability);
-
     static bool needsToKeep(const HistoricalInfo *const historicalInfo,
             const HeaderPolicy *const headerPolicy);
 
@@ -101,6 +98,8 @@
     static const int MIN_VISIBLE_LEVEL;
     static const int MAX_ELAPSED_TIME_STEP_COUNT;
     static const int DISCARD_LEVEL_ZERO_ENTRY_TIME_STEP_COUNT_THRESHOLD;
+    static const int OCCURRENCES_TO_RAISE_THE_LEVEL;
+    static const int DURATION_TO_LOWER_THE_LEVEL_IN_SECONDS;
 
     static const float UNIGRAM_COUNT_HARD_LIMIT_WEIGHT;
     static const float BIGRAM_COUNT_HARD_LIMIT_WEIGHT;
diff --git a/tests/src/com/android/inputmethod/keyboard/action/KlpActionLabelTests.java b/tests/src/com/android/inputmethod/keyboard/action/KlpActionLabelTests.java
index 74343cb..07c604e 100644
--- a/tests/src/com/android/inputmethod/keyboard/action/KlpActionLabelTests.java
+++ b/tests/src/com/android/inputmethod/keyboard/action/KlpActionLabelTests.java
@@ -131,7 +131,7 @@
                 textsSet.getText("label_done_key"));
         final ExpectedActionKey previousKey = ExpectedActionKey.newLabelKey(
                 textsSet.getText("label_previous_key"));
-        final String tag = "label=hi_ZZ system=" + systemLocale
+        final String tag = "label=" + subtype.getLocale() + " system=" + systemLocale
                 + " " + SubtypeLocaleUtils.getSubtypeNameForLogging(subtype);
         final RunInLocale<Void> job = new RunInLocale<Void>() {
             @Override
@@ -147,26 +147,34 @@
     public void testHinglishActionLabel() {
         final RichInputMethodManager richImm = RichInputMethodManager.getInstance();
         final Locale hi_ZZ = new Locale("hi", "ZZ");
-        final InputMethodSubtype hinglish = richImm.findSubtypeByLocaleAndKeyboardLayoutSet(
+        final InputMethodSubtype hiLatn = richImm.findSubtypeByLocaleAndKeyboardLayoutSet(
                 hi_ZZ.toString(), SubtypeLocaleUtils.QWERTY);
+        // This is a preliminary subtype and may not exist.
+        if (hiLatn == null) {
+            return;
+        }
         // An action label should be displayed in subtype's locale regardless of the system locale.
-        doTestActionKeysInLocaleWithKeyboardTextsSet(hinglish, hi_ZZ, hi_ZZ);
-        doTestActionKeysInLocaleWithKeyboardTextsSet(hinglish, hi_ZZ, Locale.US);
-        doTestActionKeysInLocaleWithKeyboardTextsSet(hinglish, hi_ZZ, Locale.FRENCH);
-        doTestActionKeysInLocaleWithKeyboardTextsSet(hinglish, hi_ZZ, Locale.ITALIAN);
-        doTestActionKeysInLocaleWithKeyboardTextsSet(hinglish, hi_ZZ, Locale.JAPANESE);
+        doTestActionKeysInLocaleWithKeyboardTextsSet(hiLatn, hi_ZZ, new Locale("hi"));
+        doTestActionKeysInLocaleWithKeyboardTextsSet(hiLatn, hi_ZZ, Locale.US);
+        doTestActionKeysInLocaleWithKeyboardTextsSet(hiLatn, hi_ZZ, Locale.FRENCH);
+        doTestActionKeysInLocaleWithKeyboardTextsSet(hiLatn, hi_ZZ, Locale.ITALIAN);
+        doTestActionKeysInLocaleWithKeyboardTextsSet(hiLatn, hi_ZZ, Locale.JAPANESE);
     }
 
     public void testSerbianLatinActionLabel() {
         final RichInputMethodManager richImm = RichInputMethodManager.getInstance();
         final Locale sr_ZZ = new Locale("sr", "ZZ");
-        final InputMethodSubtype hinglish = richImm.findSubtypeByLocaleAndKeyboardLayoutSet(
+        final InputMethodSubtype srLatn = richImm.findSubtypeByLocaleAndKeyboardLayoutSet(
                 sr_ZZ.toString(), "serbian_qwertz");
+        // This is a preliminary subtype and may not exist.
+        if (srLatn == null) {
+            return;
+        }
         // An action label should be displayed in subtype's locale regardless of the system locale.
-        doTestActionKeysInLocaleWithKeyboardTextsSet(hinglish, sr_ZZ, sr_ZZ);
-        doTestActionKeysInLocaleWithKeyboardTextsSet(hinglish, sr_ZZ, Locale.US);
-        doTestActionKeysInLocaleWithKeyboardTextsSet(hinglish, sr_ZZ, Locale.FRENCH);
-        doTestActionKeysInLocaleWithKeyboardTextsSet(hinglish, sr_ZZ, Locale.ITALIAN);
-        doTestActionKeysInLocaleWithKeyboardTextsSet(hinglish, sr_ZZ, Locale.JAPANESE);
+        doTestActionKeysInLocaleWithKeyboardTextsSet(srLatn, sr_ZZ, new Locale("sr"));
+        doTestActionKeysInLocaleWithKeyboardTextsSet(srLatn, sr_ZZ, Locale.US);
+        doTestActionKeysInLocaleWithKeyboardTextsSet(srLatn, sr_ZZ, Locale.FRENCH);
+        doTestActionKeysInLocaleWithKeyboardTextsSet(srLatn, sr_ZZ, Locale.ITALIAN);
+        doTestActionKeysInLocaleWithKeyboardTextsSet(srLatn, sr_ZZ, Locale.JAPANESE);
     }
 }
diff --git a/tests/src/com/android/inputmethod/keyboard/layout/tests/KeyboardLayoutSetSubtypesCountTests.java b/tests/src/com/android/inputmethod/keyboard/layout/tests/KeyboardLayoutSetSubtypesCountTests.java
index 6f747b3..2134eb5 100644
--- a/tests/src/com/android/inputmethod/keyboard/layout/tests/KeyboardLayoutSetSubtypesCountTests.java
+++ b/tests/src/com/android/inputmethod/keyboard/layout/tests/KeyboardLayoutSetSubtypesCountTests.java
@@ -27,8 +27,8 @@
 
 @SmallTest
 public class KeyboardLayoutSetSubtypesCountTests extends KeyboardLayoutSetTestsBase {
-    private static final int NUMBER_OF_SUBTYPES = 85;
-    private static final int NUMBER_OF_ASCII_CAPABLE_SUBTYPES = 50;
+    private static final int NUMBER_OF_SUBTYPES = 78;
+    private static final int NUMBER_OF_ASCII_CAPABLE_SUBTYPES = 47;
     private static final int NUMBER_OF_PREDEFINED_ADDITIONAL_SUBTYPES = 2;
 
     @Override
diff --git a/tests/src/com/android/inputmethod/keyboard/layout/tests/TestsBengaliBD.java b/tests/src/com/android/inputmethod/keyboard/layout/tests/TestsBengaliBD.java
index 6262589..c39a392 100644
--- a/tests/src/com/android/inputmethod/keyboard/layout/tests/TestsBengaliBD.java
+++ b/tests/src/com/android/inputmethod/keyboard/layout/tests/TestsBengaliBD.java
@@ -16,7 +16,7 @@
 
 package com.android.inputmethod.keyboard.layout.tests;
 
-import android.test.suitebuilder.annotation.SmallTest;
+import android.test.suitebuilder.annotation.Suppress;
 
 import com.android.inputmethod.keyboard.layout.BengaliAkkhor;
 import com.android.inputmethod.keyboard.layout.LayoutBase;
@@ -29,7 +29,7 @@
 /**
  * bn_BD: Bengali (Bangladesh)/bengali_akkhor
  */
-@SmallTest
+@Suppress
 public final class TestsBengaliBD extends LayoutTestsBase {
     private static final Locale LOCALE = new Locale("bn", "BD");
     private static final LayoutBase LAYOUT = new BengaliAkkhor(new BengaliBDCustomzier(LOCALE));
diff --git a/tests/src/com/android/inputmethod/keyboard/layout/tests/TestsHinglish.java b/tests/src/com/android/inputmethod/keyboard/layout/tests/TestsHinglish.java
index 613b3bb..a8e8723 100644
--- a/tests/src/com/android/inputmethod/keyboard/layout/tests/TestsHinglish.java
+++ b/tests/src/com/android/inputmethod/keyboard/layout/tests/TestsHinglish.java
@@ -16,7 +16,7 @@
 
 package com.android.inputmethod.keyboard.layout.tests;
 
-import android.test.suitebuilder.annotation.SmallTest;
+import android.test.suitebuilder.annotation.Suppress;
 
 import com.android.inputmethod.keyboard.layout.LayoutBase;
 import com.android.inputmethod.keyboard.layout.Qwerty;
@@ -30,7 +30,7 @@
 /*
  * hi_ZZ: Hinglish/qwerty
  */
-@SmallTest
+@Suppress
 public final class TestsHinglish extends LayoutTestsBase {
     private static final Locale LOCALE = new Locale("hi", "ZZ");
     private static final LayoutBase LAYOUT = new Qwerty(new HinglishCustomizer(LOCALE));
diff --git a/tests/src/com/android/inputmethod/keyboard/layout/tests/TestsMyanmarMM.java b/tests/src/com/android/inputmethod/keyboard/layout/tests/TestsMyanmarMM.java
index b581e4a..18baa61 100644
--- a/tests/src/com/android/inputmethod/keyboard/layout/tests/TestsMyanmarMM.java
+++ b/tests/src/com/android/inputmethod/keyboard/layout/tests/TestsMyanmarMM.java
@@ -16,7 +16,7 @@
 
 package com.android.inputmethod.keyboard.layout.tests;
 
-import android.test.suitebuilder.annotation.SmallTest;
+import android.test.suitebuilder.annotation.Suppress;
 
 import com.android.inputmethod.keyboard.layout.LayoutBase;
 import com.android.inputmethod.keyboard.layout.Myanmar;
@@ -26,7 +26,7 @@
 /**
  * my_MM: Myanmar (Myanmar)/myanmar
  */
-@SmallTest
+@Suppress
 public final class TestsMyanmarMM extends LayoutTestsBase {
     private static final Locale LOCALE = new Locale("my", "MM");
     private static final LayoutBase LAYOUT = new Myanmar(LOCALE);
diff --git a/tests/src/com/android/inputmethod/keyboard/layout/tests/TestsSerbianLatin.java b/tests/src/com/android/inputmethod/keyboard/layout/tests/TestsSerbianLatin.java
index 7490d30..ea957e4 100644
--- a/tests/src/com/android/inputmethod/keyboard/layout/tests/TestsSerbianLatin.java
+++ b/tests/src/com/android/inputmethod/keyboard/layout/tests/TestsSerbianLatin.java
@@ -16,7 +16,7 @@
 
 package com.android.inputmethod.keyboard.layout.tests;
 
-import android.test.suitebuilder.annotation.SmallTest;
+import android.test.suitebuilder.annotation.Suppress;
 
 import com.android.inputmethod.keyboard.layout.LayoutBase;
 import com.android.inputmethod.keyboard.layout.SerbianQwertz;
@@ -27,7 +27,7 @@
 /**
  * sr_ZZ: Serbian (Latin)/serbian_qwertz
  */
-@SmallTest
+@Suppress
 public final class TestsSerbianLatin extends LayoutTestsBase {
     private static final Locale LOCALE = new Locale("sr", "ZZ");
     private static final LayoutBase LAYOUT = new SerbianQwertz(new SerbianLatinCustomizer(LOCALE));
diff --git a/tests/src/com/android/inputmethod/keyboard/layout/tests/TestsSerbianLatinQwerty.java b/tests/src/com/android/inputmethod/keyboard/layout/tests/TestsSerbianLatinQwerty.java
index 6d9351c..a198473 100644
--- a/tests/src/com/android/inputmethod/keyboard/layout/tests/TestsSerbianLatinQwerty.java
+++ b/tests/src/com/android/inputmethod/keyboard/layout/tests/TestsSerbianLatinQwerty.java
@@ -16,7 +16,7 @@
 
 package com.android.inputmethod.keyboard.layout.tests;
 
-import android.test.suitebuilder.annotation.SmallTest;
+import android.test.suitebuilder.annotation.Suppress;
 
 import com.android.inputmethod.keyboard.layout.LayoutBase;
 import com.android.inputmethod.keyboard.layout.Qwerty;
@@ -29,7 +29,7 @@
 /**
  * sr_ZZ: Serbian (Latin)/qwerty
  */
-@SmallTest
+@Suppress
 public final class TestsSerbianLatinQwerty extends LayoutTestsBase {
     private static final Locale LOCALE = new Locale("sr", "ZZ");
     private static final LayoutBase LAYOUT = new Qwerty(new SerbianLatinQwertyCustomizer(LOCALE));
diff --git a/tests/src/com/android/inputmethod/keyboard/layout/tests/TestsUzbek.java b/tests/src/com/android/inputmethod/keyboard/layout/tests/TestsUzbek.java
index fd12a6a..169de1f 100644
--- a/tests/src/com/android/inputmethod/keyboard/layout/tests/TestsUzbek.java
+++ b/tests/src/com/android/inputmethod/keyboard/layout/tests/TestsUzbek.java
@@ -16,7 +16,7 @@
 
 package com.android.inputmethod.keyboard.layout.tests;
 
-import android.test.suitebuilder.annotation.SmallTest;
+import android.test.suitebuilder.annotation.Suppress;
 
 import com.android.inputmethod.keyboard.layout.LayoutBase;
 import com.android.inputmethod.keyboard.layout.Uzbek;
@@ -27,7 +27,7 @@
 /**
  * uz_UZ: Uzbek (Uzbekistan)/uzbek
  */
-@SmallTest
+@Suppress
 public final class TestsUzbek extends LayoutTestsBase {
     private static final Locale LOCALE = new Locale("uz", "UZ");
     private static final LayoutBase LAYOUT = new Uzbek(new UzbekCustomizer(LOCALE));
diff --git a/tests/src/com/android/inputmethod/keyboard/layout/tests/TestsUzbekQwerty.java b/tests/src/com/android/inputmethod/keyboard/layout/tests/TestsUzbekQwerty.java
index 4c33a8c..c210da1 100644
--- a/tests/src/com/android/inputmethod/keyboard/layout/tests/TestsUzbekQwerty.java
+++ b/tests/src/com/android/inputmethod/keyboard/layout/tests/TestsUzbekQwerty.java
@@ -16,7 +16,7 @@
 
 package com.android.inputmethod.keyboard.layout.tests;
 
-import android.test.suitebuilder.annotation.SmallTest;
+import android.test.suitebuilder.annotation.Suppress;
 
 import com.android.inputmethod.keyboard.layout.LayoutBase;
 import com.android.inputmethod.keyboard.layout.Qwerty;
@@ -28,7 +28,7 @@
 /**
  * uz_UZ: Uzbek (Uzbekistan)/qwerty
  */
-@SmallTest
+@Suppress
 public final class TestsUzbekQwerty extends LayoutTestsBase {
     private static final Locale LOCALE = new Locale("uz", "UZ");
     private static final LayoutBase LAYOUT = new Qwerty(new UzbekQwertyCustomizer(LOCALE));
diff --git a/tests/src/com/android/inputmethod/latin/BinaryDictionaryDecayingTests.java b/tests/src/com/android/inputmethod/latin/BinaryDictionaryDecayingTests.java
index c3c2bb2..0e58b72 100644
--- a/tests/src/com/android/inputmethod/latin/BinaryDictionaryDecayingTests.java
+++ b/tests/src/com/android/inputmethod/latin/BinaryDictionaryDecayingTests.java
@@ -611,17 +611,23 @@
                 mCurrentTime);
         final NgramContext beginningOfSentenceContext = NgramContext.BEGINNING_OF_SENTENCE;
         onInputWordWithBeginningOfSentenceContext(binaryDictionary, "aaa", true /* isValidWord */);
+        assertFalse(binaryDictionary.isValidNgram(beginningOfSentenceContext, "aaa"));
+        onInputWordWithBeginningOfSentenceContext(binaryDictionary, "aaa", true /* isValidWord */);
         assertTrue(binaryDictionary.isValidNgram(beginningOfSentenceContext, "aaa"));
         onInputWordWithBeginningOfSentenceContext(binaryDictionary, "aaa", true /* isValidWord */);
         onInputWordWithBeginningOfSentenceContext(binaryDictionary, "bbb", true /* isValidWord */);
+        assertFalse(binaryDictionary.isValidNgram(beginningOfSentenceContext, "bbb"));
         onInputWordWithBeginningOfSentenceContext(binaryDictionary, "bbb", true /* isValidWord */);
         assertTrue(binaryDictionary.isValidNgram(beginningOfSentenceContext, "aaa"));
         assertTrue(binaryDictionary.isValidNgram(beginningOfSentenceContext, "bbb"));
         forcePassingLongTime(binaryDictionary);
         assertFalse(binaryDictionary.isValidNgram(beginningOfSentenceContext, "aaa"));
         assertFalse(binaryDictionary.isValidNgram(beginningOfSentenceContext, "bbb"));
-
         onInputWordWithBeginningOfSentenceContext(binaryDictionary, "aaa", true /* isValidWord */);
+        assertFalse(binaryDictionary.isValidNgram(beginningOfSentenceContext, "aaa"));
+        onInputWordWithBeginningOfSentenceContext(binaryDictionary, "aaa", true /* isValidWord */);
+        onInputWordWithBeginningOfSentenceContext(binaryDictionary, "bbb", true /* isValidWord */);
+        assertFalse(binaryDictionary.isValidNgram(beginningOfSentenceContext, "bbb"));
         onInputWordWithBeginningOfSentenceContext(binaryDictionary, "bbb", true /* isValidWord */);
         assertTrue(binaryDictionary.isValidNgram(beginningOfSentenceContext, "aaa"));
         assertTrue(binaryDictionary.isValidNgram(beginningOfSentenceContext, "bbb"));
diff --git a/tests/src/com/android/inputmethod/latin/personalization/ContextualDictionaryTests.java b/tests/src/com/android/inputmethod/latin/personalization/ContextualDictionaryTests.java
index 565fadb..0113099 100644
--- a/tests/src/com/android/inputmethod/latin/personalization/ContextualDictionaryTests.java
+++ b/tests/src/com/android/inputmethod/latin/personalization/ContextualDictionaryTests.java
@@ -42,8 +42,9 @@
         final ArrayList<String> dictTypes = new ArrayList<>();
         dictTypes.add(Dictionary.TYPE_CONTEXTUAL);
         final DictionaryFacilitator dictionaryFacilitator = new DictionaryFacilitator();
-        dictionaryFacilitator.resetDictionariesForTesting(getContext(), LOCALE_EN_US, dictTypes,
-                new HashMap<String, File>(), new HashMap<String, Map<String, String>>());
+        dictionaryFacilitator.resetDictionariesForTesting(getContext(),
+                new Locale[] { LOCALE_EN_US }, dictTypes, new HashMap<String, File>(),
+                new HashMap<String, Map<String, String>>());
         return dictionaryFacilitator;
     }
 
diff --git a/tests/src/com/android/inputmethod/latin/personalization/PersonalizationDictionaryTests.java b/tests/src/com/android/inputmethod/latin/personalization/PersonalizationDictionaryTests.java
index 4e7e814..afabbbd 100644
--- a/tests/src/com/android/inputmethod/latin/personalization/PersonalizationDictionaryTests.java
+++ b/tests/src/com/android/inputmethod/latin/personalization/PersonalizationDictionaryTests.java
@@ -55,8 +55,9 @@
         dictTypes.add(Dictionary.TYPE_MAIN);
         dictTypes.add(Dictionary.TYPE_PERSONALIZATION);
         final DictionaryFacilitator dictionaryFacilitator = new DictionaryFacilitator(getContext());
-        dictionaryFacilitator.resetDictionariesForTesting(getContext(), LOCALE_EN_US, dictTypes,
-                new HashMap<String, File>(), new HashMap<String, Map<String, String>>());
+        dictionaryFacilitator.resetDictionariesForTesting(getContext(),
+                new Locale[] { LOCALE_EN_US }, dictTypes, new HashMap<String, File>(),
+                new HashMap<String, Map<String, String>>());
         // Set subtypes.
         RichInputMethodManager.init(getContext());
         final RichInputMethodManager richImm = RichInputMethodManager.getInstance();
diff --git a/tests/src/com/android/inputmethod/latin/utils/SpacebarLanguageUtilsTests.java b/tests/src/com/android/inputmethod/latin/utils/SpacebarLanguageUtilsTests.java
index b766ab2..e6131cf 100644
--- a/tests/src/com/android/inputmethod/latin/utils/SpacebarLanguageUtilsTests.java
+++ b/tests/src/com/android/inputmethod/latin/utils/SpacebarLanguageUtilsTests.java
@@ -45,7 +45,6 @@
     RichInputMethodSubtype FR_CH;
     RichInputMethodSubtype DE;
     RichInputMethodSubtype DE_CH;
-    RichInputMethodSubtype HI_ZZ;
     RichInputMethodSubtype ZZ;
     RichInputMethodSubtype DE_QWERTY;
     RichInputMethodSubtype FR_QWERTZ;
@@ -55,6 +54,9 @@
     RichInputMethodSubtype ZZ_AZERTY;
     RichInputMethodSubtype ZZ_PC;
 
+    // This is a preliminary subtype and may not exist.
+    RichInputMethodSubtype HI_LATN;
+
     @Override
     protected void setUp() throws Exception {
         super.setUp();
@@ -87,8 +89,6 @@
                 Locale.GERMAN.toString(), "qwertz"));
         DE_CH = new RichInputMethodSubtype(mRichImm.findSubtypeByLocaleAndKeyboardLayoutSet(
                 "de_CH", "swiss"));
-        HI_ZZ = new RichInputMethodSubtype(mRichImm.findSubtypeByLocaleAndKeyboardLayoutSet(
-                "hi_ZZ", "qwerty"));
         ZZ = new RichInputMethodSubtype(mRichImm.findSubtypeByLocaleAndKeyboardLayoutSet(
                 SubtypeLocaleUtils.NO_LANGUAGE, "qwerty"));
         DE_QWERTY = new RichInputMethodSubtype(
@@ -112,6 +112,12 @@
         ZZ_PC = new RichInputMethodSubtype(
                 AdditionalSubtypeUtils.createAsciiEmojiCapableAdditionalSubtype(
                     SubtypeLocaleUtils.NO_LANGUAGE, "pcqwerty"));
+
+        final InputMethodSubtype hiLatn = mRichImm.findSubtypeByLocaleAndKeyboardLayoutSet(
+                "hi_ZZ", "qwerty");
+        if (hiLatn != null) {
+            HI_LATN = new RichInputMethodSubtype(hiLatn);
+        }
     }
 
     public void testAllFullDisplayNameForSpacebar() {
@@ -119,12 +125,17 @@
             final String subtypeName = SubtypeLocaleUtils
                     .getSubtypeDisplayNameInSystemLocale(subtype.getRawSubtype());
             final String spacebarText = subtype.getFullDisplayName();
-            final String languageName = SubtypeLocaleUtils
-                    .getSubtypeLocaleDisplayName(subtype.getLocale());
-            if (subtype.isNoLanguage()) {
-                assertFalse(subtypeName, spacebarText.contains(languageName));
+            final Locale[] locales = subtype.getLocales();
+            if (1 == locales.length) {
+                final String languageName = SubtypeLocaleUtils
+                        .getSubtypeLocaleDisplayName(locales[0].toString());
+                if (subtype.isNoLanguage()) {
+                    assertFalse(subtypeName, spacebarText.contains(languageName));
+                } else {
+                    assertTrue(subtypeName, spacebarText.contains(languageName));
+                }
             } else {
-                assertTrue(subtypeName, spacebarText.contains(languageName));
+                // TODO: test multi-lingual subtype spacebar display
             }
         }
     }
@@ -133,8 +144,14 @@
         for (final RichInputMethodSubtype subtype : mSubtypesList) {
             final String subtypeName = SubtypeLocaleUtils
                     .getSubtypeDisplayNameInSystemLocale(subtype.getRawSubtype());
+            final Locale[] locales = subtype.getLocales();
+            if (locales.length > 1) {
+                // TODO: test multi-lingual subtype spacebar display
+                continue;
+            }
+            final Locale locale = locales[0];
             if (SubtypeLocaleUtils.sExceptionalLocaleDisplayedInRootLocale.contains(
-                    subtype.getLocale())) {
+                    locale.toString())) {
                 // Skip test because the language part of this locale string doesn't represent
                 // the locale to be displayed on the spacebar (for example hi_ZZ and Hinglish).
                 continue;
@@ -144,7 +161,6 @@
                 assertEquals(subtypeName, SubtypeLocaleUtils.getKeyboardLayoutSetDisplayName(
                         subtype.getRawSubtype()), spacebarText);
             } else {
-                final Locale locale = SubtypeLocaleUtils.getSubtypeLocale(subtype);
                 assertEquals(subtypeName,
                         SubtypeLocaleUtils.getSubtypeLocaleDisplayName(locale.getLanguage()),
                         spacebarText);
@@ -182,8 +198,11 @@
             assertEquals("fr_CH", "Français (Suisse)", FR_CH.getFullDisplayName());
             assertEquals("de", "Deutsch", DE.getFullDisplayName());
             assertEquals("de_CH", "Deutsch (Schweiz)", DE_CH.getFullDisplayName());
-            assertEquals("hi_ZZ", "Hinglish", HI_ZZ.getFullDisplayName());
             assertEquals("zz", "QWERTY", ZZ.getFullDisplayName());
+            // This is a preliminary subtype and may not exist.
+            if (HI_LATN != null) {
+                assertEquals("hi_ZZ", "Hinglish", HI_LATN.getFullDisplayName());
+            }
 
             assertEquals("en_US", "English", EN_US.getMiddleDisplayName());
             assertEquals("en_GB", "English", EN_GB.getMiddleDisplayName());
@@ -193,8 +212,11 @@
             assertEquals("fr_CH", "Français", FR_CH.getMiddleDisplayName());
             assertEquals("de", "Deutsch", DE.getMiddleDisplayName());
             assertEquals("de_CH", "Deutsch", DE_CH.getMiddleDisplayName());
-            assertEquals("hi_ZZ", "Hinglish", HI_ZZ.getMiddleDisplayName());
             assertEquals("zz", "QWERTY", ZZ.getMiddleDisplayName());
+            // This is a preliminary subtype and may not exist.
+            if (HI_LATN != null) {
+                assertEquals("hi_ZZ", "Hinglish", HI_LATN.getMiddleDisplayName());
+            }
             return null;
         }
     };
diff --git a/tests/src/com/android/inputmethod/latin/utils/SubtypeLocaleUtilsTests.java b/tests/src/com/android/inputmethod/latin/utils/SubtypeLocaleUtilsTests.java
index c095e68..dfc3fec 100644
--- a/tests/src/com/android/inputmethod/latin/utils/SubtypeLocaleUtilsTests.java
+++ b/tests/src/com/android/inputmethod/latin/utils/SubtypeLocaleUtilsTests.java
@@ -45,7 +45,6 @@
     InputMethodSubtype FR_CH;
     InputMethodSubtype DE;
     InputMethodSubtype DE_CH;
-    InputMethodSubtype HI_ZZ;
     InputMethodSubtype ZZ;
     InputMethodSubtype DE_QWERTY;
     InputMethodSubtype FR_QWERTZ;
@@ -55,6 +54,9 @@
     InputMethodSubtype ZZ_AZERTY;
     InputMethodSubtype ZZ_PC;
 
+    // This is a preliminary subtype and may not exist.
+    InputMethodSubtype HI_LATN;
+
     @Override
     protected void setUp() throws Exception {
         super.setUp();
@@ -87,8 +89,6 @@
                 Locale.GERMAN.toString(), "qwertz");
         DE_CH = mRichImm.findSubtypeByLocaleAndKeyboardLayoutSet(
                 "de_CH", "swiss");
-        HI_ZZ = mRichImm.findSubtypeByLocaleAndKeyboardLayoutSet(
-                "hi_ZZ", "qwerty");
         ZZ = mRichImm.findSubtypeByLocaleAndKeyboardLayoutSet(
                 SubtypeLocaleUtils.NO_LANGUAGE, "qwerty");
         DE_QWERTY = AdditionalSubtypeUtils.createAsciiEmojiCapableAdditionalSubtype(
@@ -105,20 +105,27 @@
                 SubtypeLocaleUtils.NO_LANGUAGE, "azerty");
         ZZ_PC = AdditionalSubtypeUtils.createAsciiEmojiCapableAdditionalSubtype(
                 SubtypeLocaleUtils.NO_LANGUAGE, "pcqwerty");
+
+        HI_LATN = mRichImm.findSubtypeByLocaleAndKeyboardLayoutSet("hi_ZZ", "qwerty");
     }
 
     public void testAllFullDisplayName() {
         for (final RichInputMethodSubtype subtype : mSubtypesList) {
             final String subtypeName = SubtypeLocaleUtils
                     .getSubtypeDisplayNameInSystemLocale(subtype.getRawSubtype());
-            if (subtype.isNoLanguage()) {
-                final String layoutName = SubtypeLocaleUtils
-                        .getKeyboardLayoutSetDisplayName(subtype.getRawSubtype());
-                assertTrue(subtypeName, subtypeName.contains(layoutName));
+            final Locale[] locales = subtype.getLocales();
+            if (1 == locales.length) {
+                if (subtype.isNoLanguage()) {
+                    final String layoutName = SubtypeLocaleUtils
+                            .getKeyboardLayoutSetDisplayName(subtype.getRawSubtype());
+                    assertTrue(subtypeName, subtypeName.contains(layoutName));
+                } else {
+                    final String languageName = SubtypeLocaleUtils
+                            .getSubtypeLocaleDisplayNameInSystemLocale(locales[0].toString());
+                    assertTrue(subtypeName, subtypeName.contains(languageName));
+                }
             } else {
-                final String languageName = SubtypeLocaleUtils
-                        .getSubtypeLocaleDisplayNameInSystemLocale(subtype.getLocale());
-                assertTrue(subtypeName, subtypeName.contains(languageName));
+                // TODO: test multi-lingual subtype spacebar display
             }
         }
     }
@@ -132,8 +139,11 @@
         assertEquals("fr_CH", "swiss", SubtypeLocaleUtils.getKeyboardLayoutSetName(FR_CH));
         assertEquals("de", "qwertz", SubtypeLocaleUtils.getKeyboardLayoutSetName(DE));
         assertEquals("de_CH", "swiss", SubtypeLocaleUtils.getKeyboardLayoutSetName(DE_CH));
-        assertEquals("hi_ZZ", "qwerty", SubtypeLocaleUtils.getKeyboardLayoutSetName(HI_ZZ));
         assertEquals("zz", "qwerty", SubtypeLocaleUtils.getKeyboardLayoutSetName(ZZ));
+        // This is a preliminary subtype and may not exist.
+        if (HI_LATN != null) {
+            assertEquals("hi_ZZ", "qwerty", SubtypeLocaleUtils.getKeyboardLayoutSetName(HI_LATN));
+        }
 
         assertEquals("de qwerty", "qwerty", SubtypeLocaleUtils.getKeyboardLayoutSetName(DE_QWERTY));
         assertEquals("fr qwertz", "qwertz", SubtypeLocaleUtils.getKeyboardLayoutSetName(FR_QWERTZ));
@@ -188,10 +198,13 @@
                         SubtypeLocaleUtils.getSubtypeDisplayNameInSystemLocale(DE));
                 assertEquals("de_CH", "German (Switzerland)",
                         SubtypeLocaleUtils.getSubtypeDisplayNameInSystemLocale(DE_CH));
-                assertEquals("hi_ZZ", "Hinglish",
-                        SubtypeLocaleUtils.getSubtypeDisplayNameInSystemLocale(HI_ZZ));
                 assertEquals("zz", "Alphabet (QWERTY)",
                         SubtypeLocaleUtils.getSubtypeDisplayNameInSystemLocale(ZZ));
+                // This is a preliminary subtype and may not exist.
+                if (HI_LATN != null) {
+                    assertEquals("hi_ZZ", "Hinglish",
+                            SubtypeLocaleUtils.getSubtypeDisplayNameInSystemLocale(HI_LATN));
+                }
                 return null;
             }
         };
@@ -263,10 +276,13 @@
                         SubtypeLocaleUtils.getSubtypeDisplayNameInSystemLocale(DE));
                 assertEquals("de_CH", "Allemand (Suisse)",
                         SubtypeLocaleUtils.getSubtypeDisplayNameInSystemLocale(DE_CH));
-                assertEquals("hi_ZZ", "Hindi/Anglais",
-                        SubtypeLocaleUtils.getSubtypeDisplayNameInSystemLocale(HI_ZZ));
                 assertEquals("zz", "Alphabet latin (QWERTY)",
                         SubtypeLocaleUtils.getSubtypeDisplayNameInSystemLocale(ZZ));
+                // This is a preliminary subtype and may not exist.
+                if (HI_LATN != null) {
+                    assertEquals("hi_ZZ", "Hindi/Anglais",
+                            SubtypeLocaleUtils.getSubtypeDisplayNameInSystemLocale(HI_LATN));
+                }
                 return null;
             }
         };
@@ -315,9 +331,9 @@
                     .getSubtypeDisplayNameInSystemLocale(rawSubtype);
             if (rawSubtype.equals(ARABIC) || rawSubtype.equals(FARSI)
                     || rawSubtype.equals(HEBREW)) {
-                assertTrue(subtypeName, SubtypeLocaleUtils.isRtlLanguage(subtype));
+                assertTrue(subtypeName, subtype.isRtlSubtype());
             } else {
-                assertFalse(subtypeName, SubtypeLocaleUtils.isRtlLanguage(subtype));
+                assertFalse(subtypeName, subtype.isRtlSubtype());
             }
         }
     }
diff --git a/tools/dicttool/compat/android/util/Pair.java b/tools/dicttool/compat/android/util/Pair.java
index 5bf3484..ab6096e 100644
--- a/tools/dicttool/compat/android/util/Pair.java
+++ b/tools/dicttool/compat/android/util/Pair.java
@@ -17,6 +17,7 @@
 package android.util;
 
 import java.util.Arrays;
+import java.util.Objects;
 
 public class Pair<T1, T2> {
     public final T1 mFirst;
@@ -29,7 +30,8 @@
 
     @Override
     public int hashCode() {
-        return Arrays.hashCode(new Object[] { mFirst, mSecond });
+        return (mFirst == null ? 0 : mFirst.hashCode())
+                ^ (mSecond == null ? 0 : mSecond.hashCode());
     }
 
     @Override
@@ -37,7 +39,6 @@
         if (o == this) return true;
         if (!(o instanceof Pair)) return false;
         Pair<?, ?> p = (Pair<?, ?>)o;
-        return ((mFirst == null && p.mFirst == null) || mFirst.equals(p.mFirst))
-                && ((mSecond == null && p.mSecond == null) || mSecond.equals(p.mSecond));
+        return Objects.equals(mFirst, p.mFirst) && Objects.equals(mSecond, p.mSecond);
     }
 }