HTC 8X- can't set language to En-US, so can't enable Cortana!

Hey all. I have a HTC 8X and I can't set the phone language to En-US. I can change speech, region and format, but I can't touch language, which is infuriating. I've done a hard reset and there isn't any US option on the language screen. Even with US Language info installed.

I'm stumped and I really want to use Cortana now. Oh well.