(Sorry, my previous post could be confusing too).

Why not just keep a few threads with links to "proper" in-your-language forums?

As said, I don't believe just having a in-your-language forum here will be that helpful. Unless it's a "kinda-pro-user" forum (and I would like that -- in fact, I've been considering setting one of those up).

EDIT: IMHO I don't think there will be any load problems. I don't expect this to get filled with international users from day 1. More like a measly 1% of the number of English users.