diff --git a/assets/patterns/help-users-when-we-time-them-out-of-a-service/timeoutDialog.js b/assets/patterns/help-users-when-we-time-them-out-of-a-service/timeoutDialog.js
index 31f6d795..1ab233b6 100644
--- a/assets/patterns/help-users-when-we-time-them-out-of-a-service/timeoutDialog.js
+++ b/assets/patterns/help-users-when-we-time-them-out-of-a-service/timeoutDialog.js
@@ -11,7 +11,7 @@ var self = module.exports = {
     validateInput(options)
 
     var cleanupFunctions = []
-    var localisedDefaults = readCookie('PLAY_LANG') && readCookie('PLAY_LANG') === 'cy' && {
+    var localisedDefaults = document.querySelector("html").lang.startsWith("cy") && {
       title: undefined,
       message: 'Er eich diogelwch, byddwn yn eich allgofnodi cyn pen',
       keepAliveButtonText: 'Parhau i fod wedi’ch mewngofnodi',