diff --git a/utils/cjk.py b/utils/cjk.py
index 1a3dc4384..4b701ede2 100644
--- a/utils/cjk.py
+++ b/utils/cjk.py
@@ -17,7 +17,11 @@ def isCharCjk(char):
 
 
 def isStringCjk(string):
+    checked = set()
     for char in string:
+        if char in checked:
+            continue
+        checked.add(char)
         if isCharCjk(char):
             return True
     return False