Sorry guys, but according to Wikipedia ( http://en.wikipedia.org/wiki/English_language ), English ranks 3rd highest in the world with native speakers, 1 or 2 if you count all who can speak English. And this has nothing to do with US alone. You have people in UK, India, Canada, Philippines, Australia who can speak English as their native language. And don't forget to include other countries, such as Denmark, Sweden, Norway, and others, who are taught English in their schools. So please drop the Americanism argument.
There are different dialects of English (American, British, Australian, etc), but I'm sure all languages have some dialect. You might as well say that Swedish, Norwegian and Danish are dialects, since all of them can talk in their native language on public television, and everyone could understand each other without too much difficulty.
However, not releasing the game in English (even if the translations aren't 100% correct in beta) will not help give good feedback from a variety of users. If you really want a good game, look at World of Warcraft. Even the European servers have support in English, French, and German at the time of release.
