There are a few spelling differences between all three. British and Canadian add a "u" in many words like "colour" and "neighbour," and British uses an "s" in words like organise and recognise, whereas Canadian and American use a "z". Also, the word "orient" as in "disoriented" or "to be oriented" is actually "orientate," so instead of "disoriented" in Canadian or American, it's "disorientated" in British. The expressions and vocabulary used in American english differ greatly from ones in Canadian or British English, for example a "truck" is called a "lorry" in British. There are a tons of other differences in vocabulary and expressions. Hope this helps!