diff --git a/sqlalchemy_searchable/parser.py b/sqlalchemy_searchable/parser.py
index ccc2bf6..48cbcee 100644
--- a/sqlalchemy_searchable/parser.py
+++ b/sqlalchemy_searchable/parser.py
@@ -20,7 +20,7 @@
 
 
 def is_alphanumeric(c):
-    return unicodedata.category(c) in ['Lu', 'Ll', 'Nd']
+    return unicodedata.category(c) in ['Lo', 'Lu', 'Ll', 'Nd']
 
 
 all_unicode = u''.join(six.unichr(c) for c in six.moves.range(65536))