Hi Joe. The easiest way to distinguish a Canadian accent from General American is the way Canadians pronounce the "ou" words like "out" and how they pronounce the vowel in words like "thought" and "caught". In words like "thought", many Canadians pronounce the vowel as [a] instead of as a rounded vowel, as most Americans do. Most Americans pronounce the word "out" as [aut] and "around" as [@raund]. (The symbol @ is supposed to be a schwa.) In this diphthong, most Canadians replace the [a] with a schwa, so that "out" sounds like [@ut] and "around" sounds like [@r@und]. Also, most Americans pronounce a word like "got" as [gat], while most Canadians use the same vowel in that word that most Americans use in "thought". There are other differences, but these are the main ones that make Americans say to someone "Oh, you're from Canada!" There's no big difference between the two accents. Some people from the northern Midwest or the state of Washington sound almost the same as Canadians.

Different pronunciations for the stressed o in 'sorry,' and to a lesser extent, 'tomorrow.' Either of these two words can pretty much identify whether a speaker is either Canadian or from the USA. Some other differences, as mentioned above, but none so pronounced as in the word 'sorry.'