Languages in title bar

Hi, I was tinkering with the settings to display the languages. I tried to change from English (us) to English (gb), but I ended up with the British flag and said "Unknown". I tried to change the settings back to English (us), but still remains on the British flag saying "Unknown". I think this has something to do with caching perhaps? Is there a way to clear this that won't undo the current stuff I have, so it can go back to English (us) and is there a way to add UK english?