When my mom was working at Gibbs Flight Service (MYF, San Diego) one of the pilots who rented there would say, ‘Whom, I?’
While that’s true, there IS one way you can be grammatically “wrong” in using the British or American spellings.
That’s if you mix them up. Use Britsh spellings consistently, even if you’re not British; use American spellings consistently, even if you’re not American; either way, you’re grammatically correct.
But PLEASE don’t use SOME British spellings and reject others because you “like” some. I’ve known people who like “armour” but reject “honour” for example.
It is confusing and alienating to the reader to switch back and forth. Worse, it is an affectation that makes you, the writer, look like the kind of person who thinks he or she can pick and choose what rules to follow just to be cute.
Sailboat
We’re colorblind.
However, we see most other words just fine.
And you survived? I used to get beat up for that.
I looked up color in my encyclopædia. It ought to have the extra “u”. 
The country with the highest number of English speakers is, in fact, India. “Colour” wins. 
I say, “It is I.” I also answer the phone about half the time with, “This is he.” The rest of the time, I answer with, “나는 몬티 입니다.”
Of course, those responses depend on the question (and language) that precedes them.
Yeah, but we’d win in a fight. And as everyone knows, might makes right.
I once felt compelled to complain to a newspaper in Australia (the Adelaide Advertiser, if you must know) which, in its coverage of the 1987 UK General Election, kept referring to the “Labor Party”. The letter was actually printed, under the sarcastic title “Laboring A Point”.
(Yes, Giles, some, if not most, Australians use the simplified spelling.)
I know! Let’s ask John Cleese!
Yeah, but we have WalMart and SUVs and fast food and…
Okay, “colour” wins. In payment, please send Stilton and Best Bitter.
Yet the misspelling of “honour” has been documented some 50 odd years earlier in The Declaration of Independance
Hmmm… okay, not quite sure if this is appropriate for GQ, but your post just made me think of something…
if the US really thought that combat power was more important than mere numbers, wouldn’t we have:
Republicans versus Democrats – Rumble for the Union
No holds barred. Whoever wins gets to put their strongman in the white house.
Libertarians would win. We have all the guns!
My Mom is Canadian, and Dad’s American. My spelling is terrible! I can’t tell you how many basic words I have to think twice how to spell! For example, “Please write me out a cheque for the colour paints and cash for the grey paints…”
Drives me nuts!
- Jinx
It’s “us”, not “we”. Using “we” there I suppose could merely pass as extremely outdated and pretentious, but I’d argue that it’s at very least poor style. The compliment to “be” in English has always been an objective pronoun - “It’s me”, not “It’s I”; this is another case in which a rule from Latin was misapplied to English. In Latin, the compliment of any copulative had to remain in the same case as the other noun; in English, not so.
The choice that “rolls off the tongue better” is of course the correct choice; the fact that it’s more natural to say reflects that it’s the product of your underlying, unconscious mastery of English grammar, even if that goes against misbegotten ideas from prescriptivists grammar school teachers.
The Declaration of Independence is notorious nowadays for its inconsistent spelling. Such things were simply less standardized back then, and quills didn’t automatically leave squiggly red lines under misspelled words.
Once again you’ve beat me to it. Only I was going to say Repulicans and the NRA!
You sure of that fact? I mean about the number of English speakers in India. The numbers I’ve seen have usually been significantly less than those in the US. Of course whether you count people with low levels of fluency also makes a difference in the counts.
As for the words with the -our/or spelling differences, there are actually over 30 such words. I used to have a list of them somewhere, lets see… ah, here we are
arbour arbor
ardour ardor
armour armor
behaviour behavior
candour candor
clamour clamor
clangour clangor
colour color
demeanour demeanor
dolour dolor
enamour enamor
endeavour endeavor
favour favor
favourite favorite
fervour fervor
flavour flavor
harbour harbor
honour honor
humour humor
labour labor
misdemeanour misdemeanor
neighbour neighbor
neighbourhood neighborhood
odour odor
parlour parlor
paviour pavior
rancour rancor
rigour rigor
rumour rumor
saviour savior
savour savor
splendour splendor
succour succor
tumour tumor
valour valor
vapour vapor
vigour vigor
There’s lots of other British/American spelling differences, all told perhaps a thousand or so words, although many of them are just a difference in whether the last letter of a word is doubled when adding a suffix.
I wonder why? 
On a similiar note, most of the words already mentioned I have got used to seeing and have learnt to accept the difference, but the one that grates on me is fetus. I can’t explain it though.
Spelling wasn’t standardised (standardized) on either side of the Pond until Johnson and Webster produced their respective dictionaries. Until then, all spelling had been phonetic, inconsistent, and dependent upon accent. Shakespeare famously spelled his name several different ways.
The roots of particular American accents can generally be traced to original (European) settlers. Likewise social attitudes, as we sent you all our Puritans.
US English spelling will ultimately supplant UK English spelling, purely due to cultural domination and Microsoft spell checkers. A shame really, but all things must pass I suppose.
Interestingly, the Australian accent seems to be some sort of English mixed with Aboriginal inflections and cadences. Any cunning linguists among us who can shed light on this?