
The short answer is, yes, it might. Oscar Wilde wrote, "We really have everything in common with America nowadays, except, of course, the language." Although speakers of American English and British English can understand each other, there are words and expressions that can be absolutely unintelligible to the non-native.
If you need a translation for the UK, you need to work with a native speaker of British English. If the translation is for a non-UK based website, most websites use American English spelling and terms. The differences go beyond deciding whether to use "aeroplane" or "airplane":
Vocabulary: Although I know that a "tin" of peas is what I would call a can, I might be gobsmacked if someone talks to me about the "lollipop lady" (crossing guard).
Punctuation: Americans write "Mr.", "Dr.", and "U.S.". The British follow the rule that a period (or full stop) is used only when the last letter of the abbreviation is not the same as the last letter of the full word.
Idioms: Many idiomatic expressions in UK and American English are similar: both "touch wood" and "knock on wood" are easily understood. But, I'd be gobsmacked by someone saying "Bob's your uncle" if I didn't know it meant that something is easy to do.
Dates and Time: Today is 2/10/09 in Nashville, but it's 10.02.09 or 10/02/09 in Cornwall. In the UK, the 24 hour calendar is used for rail and airline schedules (or timetables as they're called), but people in the U.S. rarely use it.
Image courtesy of DG Jones
http://flickr.com/photos/dgjones/2448465241
http://www.pandltranslations.com