Phil's right, the Brits do use "Eh" (Pronounced A), but I think the way the Canadian's use it (according to the stereotype) is why it stuck. Usually in Britain, it's used to express disbelief or non-understanding, for example: "Eh? You what?" and "(Eh) What are you talkin 'bout (Eh)". From the stereotype Canadian, they seem to use it for many different types of sentences, like a filler, for no apparent reason. :P For example: "So, you're going to the cinema, eh?" or "Nice weather, eh". I stress, I'm basing solely on the stereotype I've heard. I actually have no idea if Canadian's are truly like this.