Most people are familiar with the wide range of accents and dialects of English spoken in the British Isles -- such as Liverpudlian Scouse, the drill-sargeant burr of Glasgow, upper-crust RP ("received pronunciation") on the BBC, and lilting Irish -- and across the United States -- including the broad "hey youse" of New Yawk, southern gool-ole boy, Valley Girl uptalk?, wide-mouthed Bostonian, and the Scandi-yah of the Dakotas made famous in Fargo.
However, those unfamiliar with other English-speaking countries tend to think that we have uniform accents. For instance, there's a general impression that Anglo Canadians share a common tongue. Other than the distinct dialects of the Maritimes and especially Newfoundland, that's even mostly true. Americans claim we all say "aboot" for about, but no Canadian I know actually thinks we do -- on the contrary, we think Americans say "abaht" (except for their newscasters, who are often Canadians anyway).
However, a lifelong British Columbian like me can usually detect slight differences in how someone from Ontario speaks. (I recall an Ontario-bred teacher of mine in grade 10 saying "fil-um" when talking about a film, for instance.) The highly inbred community of journalists in Toronto and Ottawa seems to have its own particularly sonorous central-Canada sound, which makes voices on national newscasts a bit grating to westerners.
My friend Leesa (an Australian currently in England) pointed out an article from her homeland describing the emergence of regional dialects in Australia too -- apparently that's something new there, and it's appearing (as these things do) in young speakers of Australian English.
Are there similar regional or class dialects in other places with many native English speakers, such as South Africa, New Zealand, or India (where it's usually a second language)? Probably. Maybe this upcoming book will reveal the answer.