diff --git a/honoka/plugins/wordsprediction.cpp b/honoka/plugins/wordsprediction.cpp
index 8c4bf8b..a5f81cb 100644
--- a/honoka/plugins/wordsprediction.cpp
+++ b/honoka/plugins/wordsprediction.cpp
@@ -58,7 +58,9 @@
     ResultList l;
     WideString word,prewords;
     for(unsigned int i = str.length();i > 0;i --) {
-        if (isalnum(utf8_wcstombs(str).c_str()[i - 1]))
+        //if (isalnum(utf8_wcstombs(str).c_str()[i - 1]))
+        if (((str[i - 1] >= 0x0041) && (str[i - 1] <= 0x005A)) ||
+            ((str[i - 1] >= 0x0061) && (str[i - 1] <= 0x007A)))
             word = str[i - 1] + word;
         else break;
     }