I have a wee bit of a Belfast accent which I have to tone down here because no one understands a word I say. I also have to slow it way down, like Jimmy C says - no one can follow us at top speed. When drunk I regress into more "culchie" talk, and can get quite Ulster Scots (it's an Ards Peninsula thing - I grew up there). If I'm doing a lecture or delivering a paper I become "awfully nice".
I love accents too, especially Norn Iron ones, and I love hearing people sing in their own "voices". Perhaps that's why I don't like all that formal classical singing - it just sounds forced and unnatural to me.