Tweak beeline speed

Change-Id: I77bbd5e1888281e838d87824dc04a574b1a7ecb7
diff --git a/native/jni/src/defines.h b/native/jni/src/defines.h
index f32ebec..62e5cb4 100644
--- a/native/jni/src/defines.h
+++ b/native/jni/src/defines.h
@@ -423,4 +423,10 @@
     // Additional proximity char which can differ by language.
     ADDITIONAL_PROXIMITY_CHAR
 } ProximityType;
+
+typedef enum {
+    NOT_A_DOUBLE_LETTER,
+    A_DOUBLE_LETTER,
+    A_STRONG_DOUBLE_LETTER
+} DoubleLetterLevel;
 #endif // LATINIME_DEFINES_H