diff --git a/java/src/com/android/inputmethod/research/ResearchLogger.java b/java/src/com/android/inputmethod/research/ResearchLogger.java
index e9ffcd981..fe31039e3 100644
--- a/java/src/com/android/inputmethod/research/ResearchLogger.java
+++ b/java/src/com/android/inputmethod/research/ResearchLogger.java
@@ -708,28 +708,45 @@ public class ResearchLogger implements SharedPreferences.OnSharedPreferenceChang
         }
     }
 
+    private static final String[] EVENTKEYS_LOG_SEGMENT_START = {
+        "logSegmentStart", "isIncludingPrivateData"
+    };
+    private static final String[] EVENTKEYS_LOG_SEGMENT_END = {
+        "logSegmentEnd"
+    };
     /* package for test */ void publishLogBuffer(final LogBuffer logBuffer,
             final ResearchLog researchLog, final boolean isIncludingPrivateData) {
+        final LogUnit openingLogUnit = new LogUnit();
+        final Object[] values = {
+            isIncludingPrivateData
+        };
+        openingLogUnit.addLogStatement(EVENTKEYS_LOG_SEGMENT_START, values,
+                false /* isPotentiallyPrivate */);
+        researchLog.publish(openingLogUnit, true /* isIncludingPrivateData */);
         LogUnit logUnit;
         while ((logUnit = logBuffer.shiftOut()) != null) {
             researchLog.publish(logUnit, isIncludingPrivateData);
         }
+        final LogUnit closingLogUnit = new LogUnit();
+        closingLogUnit.addLogStatement(EVENTKEYS_LOG_SEGMENT_END, EVENTKEYS_NULLVALUES,
+                false /* isPotentiallyPrivate */);
+        researchLog.publish(closingLogUnit, true /* isIncludingPrivateData */);
     }
 
-    private boolean hasOnlyLetters(final String word) {
+    private boolean hasLetters(final String word) {
         final int length = word.length();
         for (int i = 0; i < length; i = word.offsetByCodePoints(i, 1)) {
             final int codePoint = word.codePointAt(i);
-            if (!Character.isLetter(codePoint)) {
-                return false;
+            if (Character.isLetter(codePoint)) {
+                return true;
             }
         }
-        return true;
+        return false;
     }
 
     private void onWordComplete(final String word) {
         Log.d(TAG, "onWordComplete: " + word);
-        if (word != null && word.length() > 0 && hasOnlyLetters(word)) {
+        if (word != null && word.length() > 0 && hasLetters(word)) {
             mCurrentLogUnit.setWord(word);
             mStatistics.recordWordEntered();
         }