Yes, none of the servers are officially designated "English speaking" or whatever. They all include players from all over the world, so they have players on at all different times. (Which I kinda like. )

I've heard people say that Besaid is the unofficial roleplay server. I've also heard people say that there's an unofficial Aussie server, but I can't remember which.

I can only speak about my server, since I haven't played on any of the others. However, I seriously doubt that you'll be able to find a well-populated server that doesn't have lots of English speaking players.

If you're looking for folks to play with on Cornelia, here's the Cornelia server forum. You can try there.