American-to-Queen's English

Tonight's bit of hilarity: The deputy desk editors looked at me (and, it should be noted, the paper's deputy editor, a former New York Times writer) as though we were illiterate at the suggestion of acclimation. It seems Brits and Australians exclusively use acclimatisation (yes, with an S - it's been a grammatical rollercoaster since we've stepped off the plane).