No need to quote chequing and cheque. Them words is real.
Gotta love how Americans go against the grain by changing spellings, dropping letters, etc. Then they try to spin it like everyone else is odd for spelling it differently. We're on to you! ;-)
While 'going against the grain' might not be the correct way to phrase it, you have to reali[sz]e that the entire rest of the English speaking world spells things like that. England, Ireland, Scotland, Wales, Canada, Australia, New Zealand, etc. . .
As far as the divergence in spelling is concerned that's almost entirely due to Noah Webster who purposefully spelled things in a more Germanic way because he found the English spellings with the French influences to be distasteful.(1)
It doesn't go against most of your point, but the reali[sz]e example in particular isn't Webster's fault or an example of U.S. divergence--- it used to be spelled -ize in the UK too, and didn't really shift completely until the past few decades. It's still the form preferred by the Oxford English Dictionary: http://en.wikipedia.org/wiki/Oxford_spelling
On the others, there's a bit more of a continuum than everyone using the British spellings, though I'll agree the Commonwealth probably tilts towards more similarity with the UK than with the US. But Canadian spelling, especially, aligns with U.S. usage in a lot of respects: it generally uses -ize rather than -ise endings ("realize", not "realise"), and sides with the Americans on a lot of specific one-off differences ("tire", not "tyre"), though it sides with the U.K. spellings on -our vs. -or ("colour", not "color").
That depends entirely on whether you were educated before the Canadian Press Manual of Style declared "ize" to be their preference. They weren't nearly as successful with the or/our thing, but folks of my vintage or older almost always use "ise" while kids (from my perspective, thirty-somethings are "kids") only slightly favour "ize" -- and that's probably just to get rid of the damned squiggles from the spell-checker. (The rule of thumb is derived from exercice/exercise -- the noun form ends in "ice", a noun, the verb in "ise", which contains "is". I believe we Canadians are the only bunch who actually used the "ice" spelling to any degree, and it was primarily in the context of exercices at the ends of textbook chapters, which one duly carried out in an "exercice book" -- call it a notebook if you aren't a fifty-ish -year-old Canadian.) There has yet to be created an app that ships with a proper Canadian English spelling dictionary -- I have a text file that contains nothing but words that get flagged by either US or UK English dictionaries but are, and have been, standard Canadian spellings. Open it in the current nightmare app with the best-fit dictionary (US, UK, Canadian or generic English) and blindly click "add" till the prompt finally goes away.
America has significantly more than double the number of native English speakers of England, Scotland, Wales, Australia, New Zealand, etc... combined. Unless you're arguing that speakers in the US somehow count for less than people elsewhere, it's actually the UK & commonwealth going against the grain. Canada is a bit of an exception, using US spellings at some times and UK spellings at others.
Unless, of course, you consider the rest of the world. In India English is an official language and they spell things in the UK way. In fact anywhere I've ever seen international English used the UK spellings have been used unless they were specifically dealing with Yanks. I don't know about all of China but I wouldn't be remotely surprised to find out they use the UK spellings when corresponding in English, given the Hong Kong connection. Singapore/Malaysia uses the UK English as well. . . .
Hey, I'm half American and half Australian so I don't really have a horse in this race (or perhaps I have two) but the provincial attitudes of some Americans when it comes to language and dialect differences is annoying.
The wikipedia statistics above were for native speakers.
I live in China and have spent most my adult life in a Mandarin/Hokkien language environment. Spellings and usage here generally follow the US, but very few people could even be considered to be fluent speakers. Hong Kong does still use UK spellings, but Taiwan and Singapore have considerably more US (and in the case of Taiwan, Canadian) influence. Japan and Korea also favor US spellings. So do Mexico, Guatemala, Nicaragua, Honduras and a lot of other places you may never have visited.
Maybe you see the attitude as "provincial" because you haven't seen much of the world yourself!
In any case, from a purely pragmatic view, the US usage is standard. I know the minority of native speakers on the other side dislike it, but let's face it. Just about everyone on earth is exposed to Hollywood and US television. Even in former UK colonies such as HK or India, North American usage is widely understood. The same can't be said for Irish/British/Welsh/Australian dialects.
Both sides changed. I think 17th century English was much different from either side today, and neither side can comfortably lay claim to it.
It was the Americans, and Webster in particular, who decided to go around rationalizing the way things were spelled. It was the English who decided to go non-rhotic. We're both changing the language, and we continue changing the language every year!
Gotta love how Americans go against the grain by changing spellings, dropping letters, etc. Then they try to spin it like everyone else is odd for spelling it differently. We're on to you! ;-)