diff --git a/src/assoc.c b/src/assoc.c
index 226a3519..80a2b43c 100644
--- a/src/assoc.c
+++ b/src/assoc.c
@@ -28,7 +28,7 @@ assoc_to_string (assoc_t assoc)
   switch (assoc)
     {
     case undef_assoc:
-      return "undefined associativity";
+      return _("undefined associativity");
 
     case right_assoc:
       return "%right";