Despite the comments here I am able to select US English as the phone language, have all my region settings as US but it still didn't work.
Pretty poor but hardly Microsoft's fault. HTC need to step up and release an update.
From the symptoms you describe it sounds like a good old fashioned hardware fault. Dodgy battery would be my guess. If you don't get anything from your proper HTC charger I would send it back to where you bought it.