Index: /CKEditor/trunk/CHANGES.html
===================================================================
--- /CKEditor/trunk/CHANGES.html	(revision 7215)
+++ /CKEditor/trunk/CHANGES.html	(revision 7216)
@@ -65,4 +65,5 @@
 		<li><a href="http://dev.ckeditor.com/ticket/6212">#6212</a> : [WebKit] Editor resize may scroll the host page.</li>
 		<li><a href="http://dev.ckeditor.com/ticket/7908">#7908</a> : [IE] Unlink command is sometimes missing from the context menu of a link.</li>
+		<li><a href="http://dev.ckeditor.com/ticket/8159">#8159</a> : Editor fails to load if the browser has no default language set.</li>
 		<li>Updated the following language files:<ul>
 			<li><a href="http://dev.ckeditor.com/ticket/8128">#8128</a> : Italian;</li>
Index: /CKEditor/trunk/_source/core/lang.js
===================================================================
--- /CKEditor/trunk/_source/core/lang.js	(revision 7215)
+++ /CKEditor/trunk/_source/core/lang.js	(revision 7216)
@@ -134,5 +134,5 @@
 		{
 			var languages = this.languages;
-			probeLanguage = probeLanguage || navigator.userLanguage || navigator.language;
+			probeLanguage = probeLanguage || navigator.userLanguage || navigator.language || defaultLanguage;
 
 			var parts = probeLanguage