Actaea

But wasn't it due to the colonization of Great Britain?

Hmm, good question. But I don't think so. In India, Australia, and so on, they spoke English back in the 19th century, but it wasn't until after World War II that English became completely common worldwide, and even then, not immediately. Am I right? Or were all sorts of global meetings held in English even before that? Most likely not; I suspect there wasn't a single language used, and they relied on translators when they couldn't communicate. But I'm not a historian, so I can't say for sure.

Because I always get the feeling that it's some kind of rural accent (as paradoxical as that may sound).

Oh, but I like the American accent more... However, I'm not a fan of English in general.