diff --git a/native/jni/com_android_inputmethod_latin_BinaryDictionary.cpp b/native/jni/com_android_inputmethod_latin_BinaryDictionary.cpp
index a3d8ec1..a55b2da 100644
--- a/native/jni/com_android_inputmethod_latin_BinaryDictionary.cpp
+++ b/native/jni/com_android_inputmethod_latin_BinaryDictionary.cpp
@@ -335,7 +335,7 @@
     if (!shortcutTargetCodePoints.empty()) {
         shortcuts.emplace_back(&shortcutTargetCodePoints, shortcutProbability);
     }
-    // Use 1 for count to indicate the word has inputed.
+    // Use 1 for count to indicate the word has inputted.
     const UnigramProperty unigramProperty(isNotAWord, isBlacklisted,
             probability, timestamp, 0 /* level */, 1 /* count */, &shortcuts);
     dictionary->addUnigramWord(codePoints, codePointCount, &unigramProperty);
@@ -353,8 +353,12 @@
     jsize word1Length = env->GetArrayLength(word1);
     int word1CodePoints[word1Length];
     env->GetIntArrayRegion(word1, 0, word1Length, word1CodePoints);
-    dictionary->addBigramWords(word0CodePoints, word0Length, word1CodePoints,
-            word1Length, probability, timestamp);
+    const std::vector<int> bigramTargetCodePoints(
+            word1CodePoints, word1CodePoints + word1Length);
+    // Use 1 for count to indicate the bigram has inputted.
+    const BigramProperty bigramProperty(&bigramTargetCodePoints, probability,
+            timestamp, 0 /* level */, 1 /* count */);
+    dictionary->addBigramWords(word0CodePoints, word0Length, &bigramProperty);
 }
 
 static void latinime_BinaryDictionary_removeBigramWords(JNIEnv *env, jclass clazz, jlong dict,
@@ -437,14 +441,18 @@
                     env->GetIntField(languageModelParam, shortcutProbabilityFieldId);
             shortcuts.emplace_back(&shortcutTargetCodePoints, shortcutProbability);
         }
-        // Use 1 for count to indicate the word has inputed.
+        // Use 1 for count to indicate the word has inputted.
         const UnigramProperty unigramProperty(isNotAWord, isBlacklisted,
                 unigramProbability, timestamp, 0 /* level */, 1 /* count */, &shortcuts);
         dictionary->addUnigramWord(word1CodePoints, word1Length, &unigramProperty);
         if (word0) {
             jint bigramProbability = env->GetIntField(languageModelParam, bigramProbabilityFieldId);
-            dictionary->addBigramWords(word0CodePoints, word0Length, word1CodePoints, word1Length,
-                    bigramProbability, timestamp);
+            const std::vector<int> bigramTargetCodePoints(
+                    word1CodePoints, word1CodePoints + word1Length);
+            // Use 1 for count to indicate the bigram has inputted.
+            const BigramProperty bigramProperty(&bigramTargetCodePoints, bigramProbability,
+                    timestamp, 0 /* level */, 1 /* count */);
+            dictionary->addBigramWords(word0CodePoints, word0Length, &bigramProperty);
         }
         if (dictionary->needsToRunGC(true /* mindsBlockByGC */)) {
             return i + 1;
@@ -558,11 +566,9 @@
                 return false;
             }
         }
-        for (const BigramProperty &bigarmProperty : *wordProperty.getBigramProperties()) {
-            const std::vector<int> *targetCodePoints = bigarmProperty.getTargetCodePoints();
+        for (const BigramProperty &bigramProperty : *wordProperty.getBigramProperties()) {
             if (!dictionaryStructureWithBufferPolicy->addBigramWords(wordCodePoints, wordLength,
-                    targetCodePoints->data(), targetCodePoints->size(),
-                    bigarmProperty.getProbability(), bigarmProperty.getTimestamp())) {
+                    &bigramProperty)) {
                 LogUtils::logToJava(env, "Cannot add bigram to the new dict.");
                 return false;
             }
diff --git a/native/jni/src/suggest/core/dictionary/dictionary.cpp b/native/jni/src/suggest/core/dictionary/dictionary.cpp
index e288413..fdc8936 100644
--- a/native/jni/src/suggest/core/dictionary/dictionary.cpp
+++ b/native/jni/src/suggest/core/dictionary/dictionary.cpp
@@ -88,11 +88,10 @@
     mDictionaryStructureWithBufferPolicy->addUnigramWord(word, length, unigramProperty);
 }
 
-void Dictionary::addBigramWords(const int *const word0, const int length0, const int *const word1,
-        const int length1, const int probability, const int timestamp) {
+void Dictionary::addBigramWords(const int *const word0, const int length0,
+        const BigramProperty *const bigramProperty) {
     TimeKeeper::setCurrentTime();
-    mDictionaryStructureWithBufferPolicy->addBigramWords(word0, length0, word1, length1,
-            probability, timestamp);
+    mDictionaryStructureWithBufferPolicy->addBigramWords(word0, length0, bigramProperty);
 }
 
 void Dictionary::removeBigramWords(const int *const word0, const int length0,
diff --git a/native/jni/src/suggest/core/dictionary/dictionary.h b/native/jni/src/suggest/core/dictionary/dictionary.h
index b6149b3..f0a7e5b 100644
--- a/native/jni/src/suggest/core/dictionary/dictionary.h
+++ b/native/jni/src/suggest/core/dictionary/dictionary.h
@@ -76,8 +76,8 @@
     void addUnigramWord(const int *const codePoints, const int codePointCount,
             const UnigramProperty *const unigramProperty);
 
-    void addBigramWords(const int *const word0, const int length0, const int *const word1,
-            const int length1, const int probability, const int timestamp);
+    void addBigramWords(const int *const word0, const int length0,
+            const BigramProperty *const bigramProperty);
 
     void removeBigramWords(const int *const word0, const int length0, const int *const word1,
             const int length1);
diff --git a/native/jni/src/suggest/core/policy/dictionary_structure_with_buffer_policy.h b/native/jni/src/suggest/core/policy/dictionary_structure_with_buffer_policy.h
index 807f9b8..ce5a49f 100644
--- a/native/jni/src/suggest/core/policy/dictionary_structure_with_buffer_policy.h
+++ b/native/jni/src/suggest/core/policy/dictionary_structure_with_buffer_policy.h
@@ -73,8 +73,8 @@
             const UnigramProperty *const unigramProperty) = 0;
 
     // Returns whether the update was success or not.
-    virtual bool addBigramWords(const int *const word0, const int length0, const int *const word1,
-            const int length1, const int probability, const int timestamp) = 0;
+    virtual bool addBigramWords(const int *const word0, const int length0,
+            const BigramProperty *const bigramProperty) = 0;
 
     // Returns whether the update was success or not.
     virtual bool removeBigramWords(const int *const word0, const int length0,
diff --git a/native/jni/src/suggest/policyimpl/dictionary/bigram/ver4_bigram_list_policy.cpp b/native/jni/src/suggest/policyimpl/dictionary/bigram/ver4_bigram_list_policy.cpp
index 1645039..9e584b4 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/bigram/ver4_bigram_list_policy.cpp
+++ b/native/jni/src/suggest/policyimpl/dictionary/bigram/ver4_bigram_list_policy.cpp
@@ -16,6 +16,7 @@
 
 #include "suggest/policyimpl/dictionary/bigram/ver4_bigram_list_policy.h"
 
+#include "suggest/core/dictionary/property/bigram_property.h"
 #include "suggest/policyimpl/dictionary/bigram/bigram_list_read_write_utils.h"
 #include "suggest/policyimpl/dictionary/header/header_policy.h"
 #include "suggest/policyimpl/dictionary/structure/v4/content/bigram_dict_content.h"
@@ -49,13 +50,12 @@
 }
 
 bool Ver4BigramListPolicy::addNewEntry(const int terminalId, const int newTargetTerminalId,
-        const int newProbability, const int timestamp, bool *const outAddedNewEntry) {
+        const BigramProperty *const bigramProperty, bool *const outAddedNewEntry) {
     // 1. The word has no bigrams yet.
     // 2. The word has bigrams, and there is the target in the list.
     // 3. The word has bigrams, and there is an invalid entry that can be reclaimed.
     // 4. The word has bigrams. We have to append new bigram entry to the list.
     // 5. Same as 4, but the list is the last entry of the content file.
-
     if (outAddedNewEntry) {
         *outAddedNewEntry = false;
     }
@@ -69,7 +69,7 @@
         const BigramEntry newBigramEntry(false /* hasNext */, NOT_A_PROBABILITY,
                 newTargetTerminalId);
         const BigramEntry bigramEntryToWrite = createUpdatedBigramEntryFrom(&newBigramEntry,
-                newProbability, timestamp);
+                bigramProperty);
         // Write an entry.
         const int writingPos =  mBigramDictContent->getBigramListHeadPos(terminalId);
         if (!mBigramDictContent->writeBigramEntry(&bigramEntryToWrite, writingPos)) {
@@ -102,7 +102,7 @@
         const BigramEntry newBigramEntry(false /* hasNext */, NOT_A_PROBABILITY,
                 newTargetTerminalId);
         const BigramEntry bigramEntryToWrite = createUpdatedBigramEntryFrom(
-                &newBigramEntry, newProbability, timestamp);
+                &newBigramEntry, bigramProperty);
         if (!mBigramDictContent->writeBigramEntryAtTail(&bigramEntryToWrite)) {
             return false;
         }
@@ -128,7 +128,7 @@
     const BigramEntry updatedBigramEntry =
             originalBigramEntry.updateTargetTerminalIdAndGetEntry(newTargetTerminalId);
     const BigramEntry bigramEntryToWrite = createUpdatedBigramEntryFrom(
-            &updatedBigramEntry, newProbability, timestamp);
+            &updatedBigramEntry, bigramProperty);
     return mBigramDictContent->writeBigramEntry(&bigramEntryToWrite, entryPosToUpdate);
 }
 
@@ -253,19 +253,19 @@
 }
 
 const BigramEntry Ver4BigramListPolicy::createUpdatedBigramEntryFrom(
-        const BigramEntry *const originalBigramEntry, const int newProbability,
-        const int timestamp) const {
+        const BigramEntry *const originalBigramEntry,
+        const BigramProperty *const bigramProperty) const {
     // TODO: Consolidate historical info and probability.
     if (mHeaderPolicy->hasHistoricalInfoOfWords()) {
-        // Use 1 for count to indicate the bigram has inputed.
-        const HistoricalInfo historicalInfoForUpdate(timestamp, 0 /* level */, 1 /* count */);
+        const HistoricalInfo historicalInfoForUpdate(bigramProperty->getTimestamp(),
+                bigramProperty->getLevel(), bigramProperty->getCount());
         const HistoricalInfo updatedHistoricalInfo =
                 ForgettingCurveUtils::createUpdatedHistoricalInfo(
-                        originalBigramEntry->getHistoricalInfo(), newProbability,
+                        originalBigramEntry->getHistoricalInfo(), bigramProperty->getProbability(),
                         &historicalInfoForUpdate, mHeaderPolicy);
         return originalBigramEntry->updateHistoricalInfoAndGetEntry(&updatedHistoricalInfo);
     } else {
-        return originalBigramEntry->updateProbabilityAndGetEntry(newProbability);
+        return originalBigramEntry->updateProbabilityAndGetEntry(bigramProperty->getProbability());
     }
 }
 
diff --git a/native/jni/src/suggest/policyimpl/dictionary/bigram/ver4_bigram_list_policy.h b/native/jni/src/suggest/policyimpl/dictionary/bigram/ver4_bigram_list_policy.h
index c1f3335..1613941 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/bigram/ver4_bigram_list_policy.h
+++ b/native/jni/src/suggest/policyimpl/dictionary/bigram/ver4_bigram_list_policy.h
@@ -24,6 +24,7 @@
 namespace latinime {
 
 class BigramDictContent;
+class BigramProperty;
 class HeaderPolicy;
 class TerminalPositionLookupTable;
 
@@ -43,8 +44,8 @@
         // Do nothing because we don't need to skip bigram lists in ver4 dictionaries.
     }
 
-    bool addNewEntry(const int terminalId, const int newTargetTerminalId, const int newProbability,
-            const int timestamp, bool *const outAddedNewEntry);
+    bool addNewEntry(const int terminalId, const int newTargetTerminalId,
+            const BigramProperty *const bigramProperty, bool *const outAddedNewEntry);
 
     bool removeEntry(const int terminalId, const int targetTerminalId);
 
@@ -60,7 +61,7 @@
             int *const outTailEntryPos) const;
 
     const BigramEntry createUpdatedBigramEntryFrom(const BigramEntry *const originalBigramEntry,
-            const int newProbability, const int timestamp) const;
+            const BigramProperty *const bigramProperty) const;
 
     bool updateHasNextFlag(const bool hasNext, const int bigramEntryPos);
 
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_updating_helper.cpp b/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_updating_helper.cpp
index a527f03..9e57585 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_updating_helper.cpp
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_updating_helper.cpp
@@ -85,13 +85,13 @@
 }
 
 bool DynamicPtUpdatingHelper::addBigramWords(const int word0Pos, const int word1Pos,
-        const int probability, const int timestamp, bool *const outAddedNewBigram) {
+        const BigramProperty *const bigramProperty, bool *const outAddedNewBigram) {
     const PtNodeParams sourcePtNodeParams(
             mPtNodeReader->fetchNodeInfoInBufferFromPtNodePos(word0Pos));
     const PtNodeParams targetPtNodeParams(
             mPtNodeReader->fetchNodeInfoInBufferFromPtNodePos(word1Pos));
-    return mPtNodeWriter->addNewBigramEntry(&sourcePtNodeParams, &targetPtNodeParams, probability,
-            timestamp, outAddedNewBigram);
+    return mPtNodeWriter->addNewBigramEntry(&sourcePtNodeParams, &targetPtNodeParams,
+            bigramProperty, outAddedNewBigram);
 }
 
 // Remove a bigram relation from word0Pos to word1Pos.
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_updating_helper.h b/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_updating_helper.h
index 44914fe..f10d15a 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_updating_helper.h
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_updating_helper.h
@@ -22,6 +22,7 @@
 
 namespace latinime {
 
+class BigramProperty;
 class BufferWithExtendableBuffer;
 class DynamicPtReadingHelper;
 class PtNodeReader;
@@ -42,8 +43,8 @@
             const UnigramProperty *const unigramProperty, bool *const outAddedNewUnigram);
 
     // Add a bigram relation from word0Pos to word1Pos.
-    bool addBigramWords(const int word0Pos, const int word1Pos, const int probability,
-            const int timestamp, bool *const outAddedNewBigram);
+    bool addBigramWords(const int word0Pos, const int word1Pos,
+            const BigramProperty *const bigramProperty, bool *const outAddedNewBigram);
 
     // Remove a bigram relation from word0Pos to word1Pos.
     bool removeBigramWords(const int word0Pos, const int word1Pos);
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/pt_node_writer.h b/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/pt_node_writer.h
index cbca3fe..a8029f7 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/pt_node_writer.h
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/pt_node_writer.h
@@ -24,6 +24,7 @@
 
 namespace latinime {
 
+class BigramProperty;
 class UnigramProperty;
 
 // Interface class used to write PtNode information.
@@ -70,7 +71,7 @@
             const UnigramProperty *const unigramProperty, int *const ptNodeWritingPos) = 0;
 
     virtual bool addNewBigramEntry(const PtNodeParams *const sourcePtNodeParams,
-            const PtNodeParams *const targetPtNodeParam, const int probability, const int timestamp,
+            const PtNodeParams *const targetPtNodeParam, const BigramProperty *const bigramProperty,
             bool *const outAddedNewBigram) = 0;
 
     virtual bool removeBigramEntry(const PtNodeParams *const sourcePtNodeParams,
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v2/patricia_trie_policy.h b/native/jni/src/suggest/policyimpl/dictionary/structure/v2/patricia_trie_policy.h
index 85f4660..6959c4e 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v2/patricia_trie_policy.h
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/v2/patricia_trie_policy.h
@@ -88,8 +88,8 @@
         return false;
     }
 
-    bool addBigramWords(const int *const word0, const int length0, const int *const word1,
-            const int length1, const int probability, const int timestamp) {
+    bool addBigramWords(const int *const word0, const int length0,
+            const BigramProperty *const bigramProperty) {
         // This method should not be called for non-updatable dictionary.
         AKLOGI("Warning: addBigramWords() is called for non-updatable dictionary.");
         return false;
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_node_writer.cpp b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_node_writer.cpp
index cc3a24a..e19ef60 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_node_writer.cpp
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_node_writer.cpp
@@ -223,11 +223,10 @@
 }
 
 bool Ver4PatriciaTrieNodeWriter::addNewBigramEntry(
-        const PtNodeParams *const sourcePtNodeParams,
-        const PtNodeParams *const targetPtNodeParam, const int probability, const int timestamp,
-        bool *const outAddedNewBigram) {
+        const PtNodeParams *const sourcePtNodeParams, const PtNodeParams *const targetPtNodeParam,
+        const BigramProperty *const bigramProperty, bool *const outAddedNewBigram) {
     if (!mBigramPolicy->addNewEntry(sourcePtNodeParams->getTerminalId(),
-            targetPtNodeParam->getTerminalId(), probability, timestamp, outAddedNewBigram)) {
+            targetPtNodeParam->getTerminalId(), bigramProperty, outAddedNewBigram)) {
         AKLOGE("Cannot add new bigram entry. terminalId: %d, targetTerminalId: %d",
                 sourcePtNodeParams->getTerminalId(), targetPtNodeParam->getTerminalId());
         return false;
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_node_writer.h b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_node_writer.h
index f20d3a2..e90bc44 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_node_writer.h
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_node_writer.h
@@ -76,7 +76,7 @@
             const UnigramProperty *const unigramProperty, int *const ptNodeWritingPos);
 
     virtual bool addNewBigramEntry(const PtNodeParams *const sourcePtNodeParams,
-            const PtNodeParams *const targetPtNodeParam, const int probability, const int timestamp,
+            const PtNodeParams *const targetPtNodeParam, const BigramProperty *const bigramProperty,
             bool *const outAddedNewBigram);
 
     virtual bool removeBigramEntry(const PtNodeParams *const sourcePtNodeParams,
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 9999e06..2fb3dec 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
@@ -209,8 +209,7 @@
 }
 
 bool Ver4PatriciaTriePolicy::addBigramWords(const int *const word0, const int length0,
-        const int *const word1, const int length1, const int probability,
-        const int timestamp) {
+        const BigramProperty *const bigramProperty) {
     if (!mBuffers->isUpdatable()) {
         AKLOGI("Warning: addBigramWords() is called for non-updatable dictionary.");
         return false;
@@ -220,9 +219,10 @@
                 mDictBuffer->getTailPosition());
         return false;
     }
-    if (length0 > MAX_WORD_LENGTH || length1 > MAX_WORD_LENGTH) {
+    if (length0 > MAX_WORD_LENGTH
+            || bigramProperty->getTargetCodePoints()->size() > MAX_WORD_LENGTH) {
         AKLOGE("Either src word or target word is too long to insert the bigram to the dictionary. "
-                "length0: %d, length1: %d", length0, length1);
+                "length0: %d, length1: %d", length0, bigramProperty->getTargetCodePoints()->size());
         return false;
     }
     const int word0Pos = getTerminalPtNodePositionOfWord(word0, length0,
@@ -230,14 +230,14 @@
     if (word0Pos == NOT_A_DICT_POS) {
         return false;
     }
-    const int word1Pos = getTerminalPtNodePositionOfWord(word1, length1,
-            false /* forceLowerCaseSearch */);
+    const int word1Pos = getTerminalPtNodePositionOfWord(
+            bigramProperty->getTargetCodePoints()->data(),
+            bigramProperty->getTargetCodePoints()->size(), false /* forceLowerCaseSearch */);
     if (word1Pos == NOT_A_DICT_POS) {
         return false;
     }
     bool addedNewBigram = false;
-    if (mUpdatingHelper.addBigramWords(word0Pos, word1Pos, probability, timestamp,
-            &addedNewBigram)) {
+    if (mUpdatingHelper.addBigramWords(word0Pos, word1Pos, bigramProperty, &addedNewBigram)) {
         if (addedNewBigram) {
             mBigramCount++;
         }
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_policy.h b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_policy.h
index 8f981de..86c1c5b 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_policy.h
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_policy.h
@@ -93,8 +93,8 @@
     bool addUnigramWord(const int *const word, const int length,
             const UnigramProperty *const unigramProperty);
 
-    bool addBigramWords(const int *const word0, const int length0, const int *const word1,
-            const int length1, const int probability, const int timestamp);
+    bool addBigramWords(const int *const word0, const int length0,
+            const BigramProperty *const bigramProperty);
 
     bool removeBigramWords(const int *const word0, const int length0, const int *const word1,
             const int length1);
diff --git a/tests/src/com/android/inputmethod/latin/BinaryDictionaryDecayingTests.java b/tests/src/com/android/inputmethod/latin/BinaryDictionaryDecayingTests.java
index aed24c5..35d9a4e 100644
--- a/tests/src/com/android/inputmethod/latin/BinaryDictionaryDecayingTests.java
+++ b/tests/src/com/android/inputmethod/latin/BinaryDictionaryDecayingTests.java
@@ -580,7 +580,6 @@
         final BinaryDictionary binaryDictionary = new BinaryDictionary(dictFile.getAbsolutePath(),
                 0 /* offset */, dictFile.length(), true /* useFullEditDistance */,
                 Locale.getDefault(), TEST_LOCALE, true /* isUpdatable */);
-        // TODO: Add tests for bigrams when the implementation gets ready.
         addUnigramWord(binaryDictionary, "aaa", DUMMY_PROBABILITY);
         assertTrue(binaryDictionary.isValidWord("aaa"));
         addUnigramWord(binaryDictionary, "bbb", Dictionary.NOT_A_PROBABILITY);
@@ -590,6 +589,11 @@
         addUnigramWord(binaryDictionary, "ccc", DUMMY_PROBABILITY);
         addUnigramWord(binaryDictionary, "ccc", DUMMY_PROBABILITY);
         addUnigramWord(binaryDictionary, "ccc", DUMMY_PROBABILITY);
+        addUnigramWord(binaryDictionary, "abc", DUMMY_PROBABILITY);
+        addBigramWords(binaryDictionary, "aaa", "abc", DUMMY_PROBABILITY);
+        assertTrue(binaryDictionary.isValidBigram("aaa", "abc"));
+        addBigramWords(binaryDictionary, "aaa", "bbb", Dictionary.NOT_A_PROBABILITY);
+        assertFalse(binaryDictionary.isValidBigram("aaa", "bbb"));
 
         assertEquals(fromFormatVersion, binaryDictionary.getFormatVersion());
         assertTrue(binaryDictionary.migrateTo(toFormatVersion));
@@ -600,6 +604,10 @@
         assertTrue(binaryDictionary.getFrequency("aaa") < binaryDictionary.getFrequency("ccc"));
         addUnigramWord(binaryDictionary, "bbb", Dictionary.NOT_A_PROBABILITY);
         assertTrue(binaryDictionary.isValidWord("bbb"));
+        assertTrue(binaryDictionary.isValidBigram("aaa", "abc"));
+        assertFalse(binaryDictionary.isValidBigram("aaa", "bbb"));
+        addBigramWords(binaryDictionary, "aaa", "bbb", Dictionary.NOT_A_PROBABILITY);
+        assertTrue(binaryDictionary.isValidBigram("aaa", "bbb"));
         binaryDictionary.close();
         dictFile.delete();
     }