Careful about making generalizations about all North Americans! I recall my mother complaining about talking to someone in the Southern US who talked way, way too slow for her. I've also found that people from New Brunswick (an east coast province of Canada) seem to talk really, really slow.

Also I think we are much less used to an ANZAC accent (is this a correct use of the word ANZAC?) than you are used to the American accent (because of TV and movies). So at a normal speed you can understand a Canadian or American but we might not be able to understand you!