Lately, however, I have been checking out Authonomy, the HarperCollins online workshop/slushpile/social network for writers, and I have to say it amazes me how differently two countries can use the same language. I suppose it's not so surprising considering how long we've been separate politically, but still, for any story that is contemporary (as opposed to futuristic) I can usually tell right away if the writer is British or American. Usually it's just a matter of unfamiliar idioms ("John kept Mary on for closing," "a manky uniform," "children from the bogs," etc.). The Australians are harder to spot.
I wonder if the day will come when we can no longer communicate? I guess the Internet and television make that less likely.