Actualización

main/template/default/extrafield/translate.tpl

@@ -0,0 +1,8 @@
+{{ form }}
+<script>
+    $(document).on('ready', function () {
+        $('select[name="sub_language"]').on('change', function () {
+            location.href += '&sub_language=' + this.value;
+        });
+    });
+</script>