Reading the posting from beenee a few down, it struck me as interesting as to where accents come from anyway. I can imagine the various dialects in Britain originated from the different languages we used to use many many years ago (?), but what about America - how did they get that distinctive twang, and Australia - likewise the drawl. I can hazzard a guess re: S. Africa as I think that came from the Dutch. Yes, I know, I'm bored.
I believe the American accent ordinates from the nasally way the 17th Century Puritans spoke who settled in New England. Australian is a mix of Cockney & Irish who made up the majority initial deportees.