You don't speak with a British accent. You always speak with proper gramar and sometimes you use fairly archaic terms. Though this isn't British, people tend to think that if you don't speak like them, you must be a Brit. Don't worry, I get it too. And seriously, you don't sound British. Trust me, you know I'm quite adept at hearing accents.
-me
p.s. I told you you'd like your present :-p