No, I don’t think we’ve enabled that setting, and so there’s no profile page to have a language. We don’t yet offer a multilingual service, so everything is in English. And it’d be a different kind of weird if my browser were suddenly asking for Arabic content.
Part of the current weirdness is that this only seems to affect the trust level display string in the admin interface dropdowns.
All other text that I’ve seen both in the admin interface and on the forum is in English. It doesn’t seem to affect anything functionally.