Hmmm, I'm an American with several British friends, and I've never heard them complain about 'hi' or 'yeah.' My friend from Liverpool has complained about my use of the word 'whatever', said it makes me sound very American haha. Anyways, most of the time they're just odd words here and there. Here's a pretty useful list: http://www.hintsandthings.co.uk/library/words2.htm Hope this helps!