diff --git a/java/src/com/android/inputmethod/latin/DictionaryFacilitator.java b/java/src/com/android/inputmethod/latin/DictionaryFacilitator.java
index 47aaead..e1acf3d 100644
--- a/java/src/com/android/inputmethod/latin/DictionaryFacilitator.java
+++ b/java/src/com/android/inputmethod/latin/DictionaryFacilitator.java
@@ -24,6 +24,7 @@
 
 import com.android.inputmethod.annotations.UsedForTesting;
 import com.android.inputmethod.keyboard.ProximityInfo;
+import com.android.inputmethod.latin.ExpandableBinaryDictionary.AddMultipleDictionaryEntriesCallback;
 import com.android.inputmethod.latin.PrevWordsInfo.WordInfo;
 import com.android.inputmethod.latin.SuggestedWords.SuggestedWordInfo;
 import com.android.inputmethod.latin.personalization.ContextualDictionary;
@@ -36,7 +37,6 @@
 import com.android.inputmethod.latin.utils.DistracterFilterCheckingExactMatchesAndSuggestions;
 import com.android.inputmethod.latin.utils.DistracterFilterCheckingIsInDictionary;
 import com.android.inputmethod.latin.utils.ExecutorUtils;
-import com.android.inputmethod.latin.utils.LanguageModelParam;
 import com.android.inputmethod.latin.utils.SuggestionResults;
 
 import java.io.File;
@@ -67,6 +67,7 @@
     // To synchronize assigning mDictionaryGroup to ensure closing dictionaries.
     private final Object mLock = new Object();
     private final DistracterFilter mDistracterFilter;
+    private final PersonalizationDictionaryFacilitator mPersonalizationDictionaryFacilitator;
 
     private static final String[] DICT_TYPES_ORDERED_TO_GET_SUGGESTIONS =
             new String[] {
@@ -174,14 +175,18 @@
 
     public DictionaryFacilitator() {
         mDistracterFilter = DistracterFilter.EMPTY_DISTRACTER_FILTER;
+        mPersonalizationDictionaryFacilitator = null;
     }
 
     public DictionaryFacilitator(final Context context) {
         mDistracterFilter = new DistracterFilterCheckingExactMatchesAndSuggestions(context);
+        mPersonalizationDictionaryFacilitator =
+                new PersonalizationDictionaryFacilitator(context, mDistracterFilter);
     }
 
     public void updateEnabledSubtypes(final List<InputMethodSubtype> enabledSubtypes) {
         mDistracterFilter.updateEnabledSubtypes(enabledSubtypes);
+        mPersonalizationDictionaryFacilitator.updateEnabledSubtypes(enabledSubtypes);
     }
 
     public Locale getLocale() {
@@ -353,6 +358,9 @@
             dictionaryGroup.closeDict(dictType);
         }
         mDistracterFilter.close();
+        if (mPersonalizationDictionaryFacilitator != null) {
+            mPersonalizationDictionaryFacilitator.close();
+        }
     }
 
     @UsedForTesting
@@ -372,11 +380,11 @@
     }
 
     public void flushPersonalizationDictionary() {
-        final ExpandableBinaryDictionary personalizationDict =
+        final ExpandableBinaryDictionary personalizationDictUsedForSuggestion =
                 mDictionaryGroup.getSubDict(Dictionary.TYPE_PERSONALIZATION);
-        if (personalizationDict != null) {
-            personalizationDict.asyncFlushBinaryDictionary();
-        }
+        mPersonalizationDictionaryFacilitator.flushPersonalizationDictionariesToUpdate(
+                personalizationDictUsedForSuggestion);
+        mDistracterFilter.close();
     }
 
     public void waitForLoadingMainDictionary(final long timeout, final TimeUnit unit)
@@ -580,6 +588,7 @@
     // personalization dictionary.
     public void clearPersonalizationDictionary() {
         clearSubDictionary(Dictionary.TYPE_PERSONALIZATION);
+        mPersonalizationDictionaryFacilitator.clearDictionariesToUpdate();
     }
 
     public void clearContextualDictionary() {
@@ -589,30 +598,9 @@
     public void addEntriesToPersonalizationDictionary(
             final PersonalizationDataChunk personalizationDataChunk,
             final SpacingAndPunctuations spacingAndPunctuations,
-            final ExpandableBinaryDictionary.AddMultipleDictionaryEntriesCallback callback) {
-        final ExpandableBinaryDictionary personalizationDict =
-                mDictionaryGroup.getSubDict(Dictionary.TYPE_PERSONALIZATION);
-        if (personalizationDict == null) {
-            if (callback != null) {
-                callback.onFinished();
-            }
-            return;
-        }
-        // TODO: Get locale from personalizationDataChunk.mDetectedLanguage.
-        final Locale dataChunkLocale = getLocale();
-        final ArrayList<LanguageModelParam> languageModelParams =
-                LanguageModelParam.createLanguageModelParamsFrom(
-                        personalizationDataChunk.mTokens,
-                        personalizationDataChunk.mTimestampInSeconds, spacingAndPunctuations,
-                        dataChunkLocale, new DistracterFilterCheckingIsInDictionary(
-                                mDistracterFilter, personalizationDict));
-        if (languageModelParams == null || languageModelParams.isEmpty()) {
-            if (callback != null) {
-                callback.onFinished();
-            }
-            return;
-        }
-        personalizationDict.addMultipleDictionaryEntriesDynamically(languageModelParams, callback);
+            final AddMultipleDictionaryEntriesCallback callback) {
+        mPersonalizationDictionaryFacilitator.addEntriesToPersonalizationDictionariesToUpdate(
+                personalizationDataChunk, spacingAndPunctuations, callback);
     }
 
     public void addPhraseToContextualDictionary(final String[] phrase, final int probability,
diff --git a/java/src/com/android/inputmethod/latin/PersonalizationDictionaryFacilitator.java b/java/src/com/android/inputmethod/latin/PersonalizationDictionaryFacilitator.java
new file mode 100644
index 0000000..03c108f
--- /dev/null
+++ b/java/src/com/android/inputmethod/latin/PersonalizationDictionaryFacilitator.java
@@ -0,0 +1,174 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.inputmethod.latin;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Locale;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import android.content.Context;
+import android.view.inputmethod.InputMethodSubtype;
+
+import com.android.inputmethod.latin.ExpandableBinaryDictionary.AddMultipleDictionaryEntriesCallback;
+import com.android.inputmethod.latin.personalization.PersonalizationDataChunk;
+import com.android.inputmethod.latin.personalization.PersonalizationDictionary;
+import com.android.inputmethod.latin.settings.SpacingAndPunctuations;
+import com.android.inputmethod.latin.utils.DistracterFilter;
+import com.android.inputmethod.latin.utils.DistracterFilterCheckingIsInDictionary;
+import com.android.inputmethod.latin.utils.LanguageModelParam;
+import com.android.inputmethod.latin.utils.SubtypeLocaleUtils;
+
+/**
+ * Class for managing and updating personalization dictionaries.
+ */
+public class PersonalizationDictionaryFacilitator {
+    private final Context mContext;
+    private final DistracterFilter mDistracterFilter;
+    private final HashMap<String, HashSet<Locale>> mLangToLocalesMap = new HashMap<>();
+    private final HashMap<Locale, ExpandableBinaryDictionary> mPersonalizationDictsToUpdate =
+            new HashMap<>();
+
+    PersonalizationDictionaryFacilitator(final Context context,
+            final DistracterFilter distracterFilter) {
+        mContext = context;
+        mDistracterFilter = distracterFilter;
+    }
+
+    public void close() {
+        mLangToLocalesMap.clear();
+        for (final ExpandableBinaryDictionary dict : mPersonalizationDictsToUpdate.values()) {
+            dict.close();
+        }
+        mPersonalizationDictsToUpdate.clear();
+    }
+
+    public void clearDictionariesToUpdate() {
+        for (final ExpandableBinaryDictionary dict : mPersonalizationDictsToUpdate.values()) {
+            dict.clear();
+        }
+        mPersonalizationDictsToUpdate.clear();
+    }
+
+    public void updateEnabledSubtypes(final List<InputMethodSubtype> enabledSubtypes) {
+        for (final InputMethodSubtype subtype : enabledSubtypes) {
+            final Locale locale = SubtypeLocaleUtils.getSubtypeLocale(subtype);
+            final String language = locale.getLanguage();
+            final HashSet<Locale> locales = mLangToLocalesMap.get(language);
+            if (locales != null) {
+                locales.add(locale);
+            } else {
+                final HashSet<Locale> localeSet = new HashSet<>();
+                localeSet.add(locale);
+                mLangToLocalesMap.put(language, localeSet);
+            }
+        }
+    }
+
+    /**
+     * Flush personalization dictionaries to dictionary files. Close dictionaries after writing
+     * files except the dictionary that is used for generating suggestions.
+     *
+     * @param personalizationDictUsedForSuggestion the personalization dictionary used for
+     * generating suggestions that won't be closed.
+     */
+    public void flushPersonalizationDictionariesToUpdate(
+            final ExpandableBinaryDictionary personalizationDictUsedForSuggestion) {
+        for (final ExpandableBinaryDictionary personalizationDict :
+                mPersonalizationDictsToUpdate.values()) {
+            personalizationDict.asyncFlushBinaryDictionary();
+            if (personalizationDict != personalizationDictUsedForSuggestion) {
+                // Close if the dictionary is not being used for suggestion.
+                personalizationDict.close();
+            }
+        }
+        mDistracterFilter.close();
+        mPersonalizationDictsToUpdate.clear();
+    }
+
+    private ExpandableBinaryDictionary getPersonalizationDictToUpdate(final Context context,
+            final Locale locale) {
+        ExpandableBinaryDictionary personalizationDict = mPersonalizationDictsToUpdate.get(locale);
+        if (personalizationDict != null) {
+            return personalizationDict;
+        }
+        personalizationDict = PersonalizationDictionary.getDictionary(context, locale,
+                null /* dictFile */, "" /* dictNamePrefix */);
+        mPersonalizationDictsToUpdate.put(locale, personalizationDict);
+        return personalizationDict;
+    }
+
+    private void addEntriesToPersonalizationDictionariesForLocale(final Locale locale,
+            final PersonalizationDataChunk personalizationDataChunk,
+            final SpacingAndPunctuations spacingAndPunctuations,
+            final AddMultipleDictionaryEntriesCallback callback) {
+        final ExpandableBinaryDictionary personalizationDict =
+                getPersonalizationDictToUpdate(mContext, locale);
+        if (personalizationDict == null) {
+            if (callback != null) {
+                callback.onFinished();
+            }
+            return;
+        }
+        final ArrayList<LanguageModelParam> languageModelParams =
+                LanguageModelParam.createLanguageModelParamsFrom(
+                        personalizationDataChunk.mTokens,
+                        personalizationDataChunk.mTimestampInSeconds, spacingAndPunctuations,
+                        locale, new DistracterFilterCheckingIsInDictionary(
+                                mDistracterFilter, personalizationDict));
+        if (languageModelParams == null || languageModelParams.isEmpty()) {
+            if (callback != null) {
+                callback.onFinished();
+            }
+            return;
+        }
+        personalizationDict.addMultipleDictionaryEntriesDynamically(languageModelParams, callback);
+    }
+
+    public void addEntriesToPersonalizationDictionariesToUpdate(
+            final PersonalizationDataChunk personalizationDataChunk,
+            final SpacingAndPunctuations spacingAndPunctuations,
+            final AddMultipleDictionaryEntriesCallback callback) {
+        final HashSet<Locale> locales =
+                mLangToLocalesMap.get(personalizationDataChunk.mDetectedLanguage);
+        if (locales == null || locales.isEmpty()) {
+            if (callback != null) {
+                callback.onFinished();
+            }
+            return;
+        }
+        final AtomicInteger remainingTaskCount = new AtomicInteger(locales.size());
+        final AddMultipleDictionaryEntriesCallback callbackForLocales =
+                new AddMultipleDictionaryEntriesCallback() {
+                    @Override
+                    public void onFinished() {
+                        if (remainingTaskCount.decrementAndGet() == 0) {
+                            // Update tasks for all locales have been finished.
+                            if (callback != null) {
+                                callback.onFinished();
+                            }
+                        }
+                    }
+                };
+        for (final Locale locale : locales) {
+            addEntriesToPersonalizationDictionariesForLocale(locale, personalizationDataChunk,
+                    spacingAndPunctuations, callbackForLocales);
+        }
+    }
+}
diff --git a/tests/src/com/android/inputmethod/latin/personalization/PersonalizationDictionaryTests.java b/tests/src/com/android/inputmethod/latin/personalization/PersonalizationDictionaryTests.java
index e9a97ff..4e7e814 100644
--- a/tests/src/com/android/inputmethod/latin/personalization/PersonalizationDictionaryTests.java
+++ b/tests/src/com/android/inputmethod/latin/personalization/PersonalizationDictionaryTests.java
@@ -29,6 +29,7 @@
 import com.android.inputmethod.latin.Dictionary;
 import com.android.inputmethod.latin.DictionaryFacilitator;
 import com.android.inputmethod.latin.ExpandableBinaryDictionary;
+import com.android.inputmethod.latin.RichInputMethodManager;
 import com.android.inputmethod.latin.ExpandableBinaryDictionary.AddMultipleDictionaryEntriesCallback;
 import com.android.inputmethod.latin.makedict.CodePointUtils;
 import com.android.inputmethod.latin.settings.SpacingAndPunctuations;
@@ -36,6 +37,7 @@
 import android.test.AndroidTestCase;
 import android.test.suitebuilder.annotation.LargeTest;
 import android.util.Log;
+import android.view.inputmethod.InputMethodSubtype;
 
 /**
  * Unit tests for personalization dictionary
@@ -55,16 +57,28 @@
         final DictionaryFacilitator dictionaryFacilitator = new DictionaryFacilitator(getContext());
         dictionaryFacilitator.resetDictionariesForTesting(getContext(), LOCALE_EN_US, dictTypes,
                 new HashMap<String, File>(), new HashMap<String, Map<String, String>>());
+        // Set subtypes.
+        RichInputMethodManager.init(getContext());
+        final RichInputMethodManager richImm = RichInputMethodManager.getInstance();
+        final ArrayList<InputMethodSubtype> subtypes = new ArrayList<>();
+        subtypes.add(richImm.findSubtypeByLocaleAndKeyboardLayoutSet(
+                LOCALE_EN_US.toString(), "qwerty"));
+        dictionaryFacilitator.updateEnabledSubtypes(subtypes);
         return dictionaryFacilitator;
     }
 
     public void testAddManyTokens() {
         final DictionaryFacilitator dictionaryFacilitator = getDictionaryFacilitator();
         dictionaryFacilitator.clearPersonalizationDictionary();
-        final int dataChunkCount = 20;
-        final int wordCountInOneChunk = 2000;
+        final int dataChunkCount = 100;
+        final int wordCountInOneChunk = 200;
+        final int uniqueWordCount = 100;
         final Random random = new Random(System.currentTimeMillis());
         final int[] codePointSet = CodePointUtils.LATIN_ALPHABETS_LOWER;
+        final ArrayList<String> words = new ArrayList<>();
+        for (int i = 0; i < uniqueWordCount; i++) {
+            words.add(CodePointUtils.generateWord(random, codePointSet));
+        }
 
         final SpacingAndPunctuations spacingAndPunctuations =
                 new SpacingAndPunctuations(getContext().getResources());
@@ -75,7 +89,7 @@
         for (int i = 0; i < dataChunkCount; i++) {
             final ArrayList<String> tokens = new ArrayList<>();
             for (int j = 0; j < wordCountInOneChunk; j++) {
-                tokens.add(CodePointUtils.generateWord(random, codePointSet));
+                tokens.add(words.get(random.nextInt(words.size())));
             }
             final PersonalizationDataChunk personalizationDataChunk = new PersonalizationDataChunk(
                     true /* inputByUser */, tokens, timeStampInSeconds, DUMMY_PACKAGE_NAME,