American English.

Books Tim Parks in The New York Review of Books on the process differences between writing for British and American audiences. We don't speak the same language:

"I had already sorted out the spelling, in fact had written the book with an American spell check, and didn’t expect that there would be much else to do. Wrong. Almost at once there was a note saying that throughout the 300 pages my use of “carriage” for a passenger train car must be changed to “coach.” Since this is a book about trains and train travel there were ninety-eight such usages. There was also the problem that I had used the word “coach” to refer to a long distance bus. Apparently the twenty-four-hour clock was not acceptable, so the 17:25 Regionale from Milan to Verona had to become the 5:25 PM Regionale. Where I, in a discussion of prices, had written “a further 50 cents” the American edit required “a further 50 euro cents,” as if otherwise an American reader might imagine Italians were dealing in nickels and dimes."

Presumably because of years spent online and watching Hollywood movies, the differences between the different prose styles isn't as noticable to me. Perhaps it's because I'm automatically translating. Or perhaps it's that I expect a piece written by someone from a particular place to sound a particular was and my brain unconsciously adjusts accordingly.  Luckily for Parks there is room to negotiate / for negotiation.