Being an American in Tokyo, most of the English speakers I know are Brits, Aussies, and Canadians. The Brits are mostly acadamics, and their English is, as you might expect, pretty good. Scots are a pain-in-the-backside to understand, though those who have been in Japan long enough have had their accents die off to the point they might pass for Canadian. Aussies never seem to lose their accents, which are most annoying to Oxbridge Brits (those from Oxford or Cambridge). Though Canadians sound much like Americans, but I cannot stand to hear the word "a-boot", as in, "it's a-boot time you got here," or "how a-boot a beer"?