diff --git a/native/jni/src/suggest/policyimpl/dictionary/bigram/bigram_list_read_write_utils.h b/native/jni/src/suggest/policyimpl/dictionary/bigram/bigram_list_read_write_utils.h
index 9a93074..884bcd7 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/bigram/bigram_list_read_write_utils.h
+++ b/native/jni/src/suggest/policyimpl/dictionary/bigram/bigram_list_read_write_utils.h
@@ -62,6 +62,11 @@
        return flags | FLAG_ATTRIBUTE_HAS_NEXT;
    }
 
+   static AK_FORCE_INLINE BigramFlags setProbabilityInFlags(const BigramFlags flags,
+           const int probability) {
+       return (flags & (~MASK_ATTRIBUTE_PROBABILITY)) | (probability & MASK_ATTRIBUTE_PROBABILITY);
+   }
+
    // Returns true if the bigram entry is valid and put entry values into out*.
    static AK_FORCE_INLINE bool createBigramEntryAndGetFlagsAndOffsetAndOffsetFieldSize(
            const int entryPos, const int targetPos, const int probability, const bool hasNext,
diff --git a/native/jni/src/suggest/policyimpl/dictionary/bigram/dynamic_bigram_list_policy.cpp b/native/jni/src/suggest/policyimpl/dictionary/bigram/dynamic_bigram_list_policy.cpp
index ca3b64d..6a8164d 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/bigram/dynamic_bigram_list_policy.cpp
+++ b/native/jni/src/suggest/policyimpl/dictionary/bigram/dynamic_bigram_list_policy.cpp
@@ -98,8 +98,8 @@
     return true;
 }
 
-bool DynamicBigramListPolicy::addBigramEntry(const int bigramPos, const int probability,
-        int *const pos) {
+bool DynamicBigramListPolicy::addNewBigramEntryToBigramList(const int bigramPos,
+        const int probability, int *const pos) {
     const bool usesAdditionalBuffer = mBuffer->isInAdditionalBuffer(*pos);
     if (usesAdditionalBuffer) {
         *pos -= mBuffer->getOriginalBufferSize();
@@ -113,7 +113,17 @@
         // The buffer address can be changed after calling buffer writing methods.
         const uint8_t *const buffer = mBuffer->getBuffer(usesAdditionalBuffer);
         flags = BigramListReadWriteUtils::getFlagsAndForwardPointer(buffer, pos);
-        BigramListReadWriteUtils::getBigramAddressAndForwardPointer(buffer, flags, pos);
+        int originalBigramPos = BigramListReadWriteUtils::getBigramAddressAndForwardPointer(
+                buffer, flags, pos);
+        if (usesAdditionalBuffer && originalBigramPos != NOT_A_VALID_WORD_POS) {
+            originalBigramPos += mBuffer->getOriginalBufferSize();
+        }
+        if (followBigramLinkAndGetCurrentBigramPtNodePos(originalBigramPos) == bigramPos) {
+            // Update this bigram entry.
+            const BigramListReadWriteUtils::BigramFlags updatedFlags =
+                    BigramListReadWriteUtils::setProbabilityInFlags(flags, probability);
+            return mBuffer->writeUintAndAdvancePosition(updatedFlags, 1 /* size */, &entryPos);
+        }
         if (BigramListReadWriteUtils::hasNext(flags)) {
             continue;
         }
@@ -124,33 +134,35 @@
         if (!mBuffer->writeUintAndAdvancePosition(updatedFlags, 1 /* size */, &entryPos)) {
             return false;
         }
-        // Then, add a new entry after the last entry.
-        BigramListReadWriteUtils::BigramFlags newBigramFlags;
-        uint32_t newBigramOffset;
-        int newBigramOffsetFieldSize;
-        if(!BigramListReadWriteUtils::createBigramEntryAndGetFlagsAndOffsetAndOffsetFieldSize(
-                *pos, bigramPos, BigramListReadWriteUtils::getProbabilityFromFlags(flags),
-                BigramListReadWriteUtils::hasNext(flags), &newBigramFlags, &newBigramOffset,
-                &newBigramOffsetFieldSize)) {
-            continue;
-        }
-        int newEntryPos = *pos;
         if (usesAdditionalBuffer) {
-            newEntryPos += mBuffer->getOriginalBufferSize();
+            *pos += mBuffer->getOriginalBufferSize();
         }
-        // Write bigram flags.
-        if (!mBuffer->writeUintAndAdvancePosition(newBigramFlags, 1 /* size */,
-                &newEntryPos)) {
-            return false;
-        }
-        // Write bigram positon offset.
-        if (!mBuffer->writeUintAndAdvancePosition(newBigramOffset, newBigramOffsetFieldSize,
-                &newEntryPos)) {
-            return false;
-        }
+        // Then, add a new entry after the last entry.
+        return writeNewBigramEntry(bigramPos, probability, pos);
     } while(BigramListReadWriteUtils::hasNext(flags));
-    if (usesAdditionalBuffer) {
-        *pos += mBuffer->getOriginalBufferSize();
+    // We return directly from the while loop.
+    ASSERT(false);
+    return false;
+}
+
+bool DynamicBigramListPolicy::writeNewBigramEntry(const int bigramPos, const int probability,
+        int *const writingPos) {
+    BigramListReadWriteUtils::BigramFlags newBigramFlags;
+    uint32_t newBigramOffset;
+    int newBigramOffsetFieldSize;
+    if(!BigramListReadWriteUtils::createBigramEntryAndGetFlagsAndOffsetAndOffsetFieldSize(
+            *writingPos, bigramPos, probability, false /* hasNext */, &newBigramFlags,
+            &newBigramOffset, &newBigramOffsetFieldSize)) {
+        return false;
+    }
+    // Write bigram flags.
+    if (!mBuffer->writeUintAndAdvancePosition(newBigramFlags, 1 /* size */, writingPos)) {
+        return false;
+    }
+    // Write bigram positon offset.
+    if (!mBuffer->writeUintAndAdvancePosition(newBigramOffset, newBigramOffsetFieldSize,
+            writingPos)) {
+        return false;
     }
     return true;
 }
diff --git a/native/jni/src/suggest/policyimpl/dictionary/bigram/dynamic_bigram_list_policy.h b/native/jni/src/suggest/policyimpl/dictionary/bigram/dynamic_bigram_list_policy.h
index e451e31..c45e26a 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/bigram/dynamic_bigram_list_policy.h
+++ b/native/jni/src/suggest/policyimpl/dictionary/bigram/dynamic_bigram_list_policy.h
@@ -48,7 +48,10 @@
     // positions after bigram lists. This method skips invalid bigram entries.
     bool copyAllBigrams(int *const fromPos, int *const toPos);
 
-    bool addBigramEntry(const int bigramPos, const int probability, int *const pos);
+    bool addNewBigramEntryToBigramList(const int bigramPos, const int probability, int *const pos);
+
+    bool writeNewBigramEntry(const int bigramPos, const int probability,
+            int *const writingPos);
 
     // Return if targetBigramPos is found or not.
     bool removeBigram(const int bigramListPos, const int targetBigramPos);
diff --git a/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_node_reader.cpp b/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_node_reader.cpp
index e455080..7370984 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_node_reader.cpp
+++ b/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_node_reader.cpp
@@ -69,10 +69,12 @@
     if (usesAdditionalBuffer && mChildrenPos != NOT_A_DICT_POS) {
         mChildrenPos += mBuffer->getOriginalBufferSize();
     }
-    if (mSiblingPos == NOT_A_DICT_POS && DynamicPatriciaTrieReadingUtils::isMoved(mFlags)) {
-        mBigramLinkedNodePos = mChildrenPos;
-    } else {
-        mBigramLinkedNodePos = NOT_A_DICT_POS;
+    if (mSiblingPos == NOT_A_DICT_POS) {
+        if (DynamicPatriciaTrieReadingUtils::isMoved(mFlags)) {
+            mBigramLinkedNodePos = mChildrenPos;
+        } else {
+            mBigramLinkedNodePos = NOT_A_DICT_POS;
+        }
     }
     if (usesAdditionalBuffer) {
         pos += mBuffer->getOriginalBufferSize();
diff --git a/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_writing_helper.cpp b/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_writing_helper.cpp
index dbc80f6..b80b9b3 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_writing_helper.cpp
+++ b/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_writing_helper.cpp
@@ -26,6 +26,8 @@
 
 namespace latinime {
 
+const int DynamicPatriciaTrieWritingHelper::CHILDREN_POSITION_FIELD_SIZE = 3;
+
 bool DynamicPatriciaTrieWritingHelper::addUnigramWord(
         DynamicPatriciaTrieReadingHelper *const readingHelper,
         const int *const wordCodePoints, const int codePointCount, const int probability) {
@@ -79,13 +81,44 @@
 
 bool DynamicPatriciaTrieWritingHelper::addBigramWords(const int word0Pos, const int word1Pos,
         const int probability) {
+    int mMergedNodeCodePoints[MAX_WORD_LENGTH];
     DynamicPatriciaTrieNodeReader nodeReader(mBuffer, mBigramPolicy, mShortcutPolicy);
-    nodeReader.fetchNodeInfoFromBuffer(word0Pos);
-    if (nodeReader.isDeleted()) {
+    nodeReader.fetchNodeInfoFromBufferAndGetNodeCodePoints(word0Pos, MAX_WORD_LENGTH,
+            mMergedNodeCodePoints);
+    // Move node to add bigram entry.
+    const int newNodePos = mBuffer->getTailPosition();
+    if (!markNodeAsMovedAndSetPosition(&nodeReader, newNodePos, newNodePos)) {
         return false;
     }
-    // TODO: Implement.
-    return false;
+    int writingPos = newNodePos;
+    // Write a new PtNode using original PtNode's info to the tail of the dictionary.
+    if (!writePtNodeToBufferByCopyingPtNodeInfo(&nodeReader, nodeReader.getParentPos(),
+            mMergedNodeCodePoints, nodeReader.getCodePointCount(), nodeReader.getProbability(),
+            &writingPos)) {
+        return false;
+    }
+    nodeReader.fetchNodeInfoFromBuffer(newNodePos);
+    if (nodeReader.getBigramsPos() != NOT_A_DICT_POS) {
+        // Insert a new bigram entry into the existing bigram list.
+        int bigramListPos = nodeReader.getBigramsPos();
+        return mBigramPolicy->addNewBigramEntryToBigramList(word1Pos, probability, &bigramListPos);
+    } else {
+        // The PtNode doesn't have a bigram list.
+        // First, Write a bigram entry at the tail position of the PtNode.
+        if (!mBigramPolicy->writeNewBigramEntry(word1Pos, probability, &writingPos)) {
+            return false;
+        }
+        // Then, Mark as the PtNode having bigram list in the flags.
+        const PatriciaTrieReadingUtils::NodeFlags updatedFlags =
+                PatriciaTrieReadingUtils::createAndGetFlags(nodeReader.isBlacklisted(),
+                        nodeReader.isNotAWord(), nodeReader.getProbability() != NOT_A_PROBABILITY,
+                        nodeReader.getShortcutPos() != NOT_A_DICT_POS, true /* hasBigrams */,
+                        nodeReader.getCodePointCount() > 1, CHILDREN_POSITION_FIELD_SIZE);
+        writingPos = newNodePos;
+        // Write updated flags into the moved PtNode's flags field.
+        return DynamicPatriciaTrieWritingUtils::writeFlagsAndAdvancePosition(mBuffer, updatedFlags,
+                &writingPos);
+    }
 }
 
 // Remove a bigram relation from word0Pos to word1Pos.
diff --git a/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_writing_helper.h b/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_writing_helper.h
index e1b9d2e..20e35ab 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_writing_helper.h
+++ b/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_writing_helper.h
@@ -49,6 +49,8 @@
  private:
     DISALLOW_IMPLICIT_CONSTRUCTORS(DynamicPatriciaTrieWritingHelper);
 
+    static const int CHILDREN_POSITION_FIELD_SIZE;
+
     BufferWithExtendableBuffer *const mBuffer;
     DynamicBigramListPolicy *const mBigramPolicy;
     DynamicShortcutListPolicy *const mShortcutPolicy;
diff --git a/tests/src/com/android/inputmethod/latin/BinaryDictionaryTests.java b/tests/src/com/android/inputmethod/latin/BinaryDictionaryTests.java
index bf4954b..6f05d42 100644
--- a/tests/src/com/android/inputmethod/latin/BinaryDictionaryTests.java
+++ b/tests/src/com/android/inputmethod/latin/BinaryDictionaryTests.java
@@ -122,4 +122,41 @@
         assertEquals(probability, binaryDictionary.getFrequency("a"));
         assertEquals(updatedProbability, binaryDictionary.getFrequency("aaa"));
     }
+
+    public void testAddBigramWords() {
+        // TODO: Add a test to check the frequency of the bigram score which uses current value
+        // calculated in the native code
+        File dictFile = null;
+        try {
+            dictFile = createEmptyDictionaryAndGetFile("TestBinaryDictionary");
+        } catch (IOException e) {
+            fail("IOException while writing an initial dictionary : " + e);
+        } catch (UnsupportedFormatException e) {
+            fail("UnsupportedFormatException while writing an initial dictionary : " + e);
+        }
+        BinaryDictionary binaryDictionary = new BinaryDictionary(dictFile.getAbsolutePath(),
+                0 /* offset */, dictFile.length(), true /* useFullEditDistance */,
+                Locale.getDefault(), TEST_LOCALE, true /* isUpdatable */);
+
+        final int unigramProbability = 100;
+        final int bigramProbability = 10;
+        binaryDictionary.addUnigramWord("aaa", unigramProbability);
+        binaryDictionary.addUnigramWord("abb", unigramProbability);
+        binaryDictionary.addUnigramWord("bcc", unigramProbability);
+        binaryDictionary.addBigramWords("aaa", "abb", bigramProbability);
+        binaryDictionary.addBigramWords("aaa", "bcc", bigramProbability);
+        binaryDictionary.addBigramWords("abb", "aaa", bigramProbability);
+        binaryDictionary.addBigramWords("abb", "bcc", bigramProbability);
+
+        assertEquals(true, binaryDictionary.isValidBigram("aaa", "abb"));
+        assertEquals(true, binaryDictionary.isValidBigram("aaa", "bcc"));
+        assertEquals(true, binaryDictionary.isValidBigram("abb", "aaa"));
+        assertEquals(true, binaryDictionary.isValidBigram("abb", "bcc"));
+
+        assertEquals(false, binaryDictionary.isValidBigram("bcc", "aaa"));
+        assertEquals(false, binaryDictionary.isValidBigram("bcc", "bbc"));
+        assertEquals(false, binaryDictionary.isValidBigram("aaa", "aaa"));
+
+        dictFile.delete();
+    }
 }