I can't give any definitive answers (hence not posting here very often), but generally speaking these things are done by activity or perceived need. The French, German, Benelux etc communities use theirs fairly regularly, and they represent fairly large portions of the community. There are also regiments which function entirely in languages other than English, and hence the language boards are a great place for them to look for recruits or vice versa. If BCoF becomes hugely popular with Finnish players, no doubt we would see a Finnish language board, but until then it would just be a private chat room for a handful of people.
That being said, if there are a significant number of Finns on the forums already that we're unaware of, feel free to PM Duuring with a list of Finns who would be interested in it. The same obviously applies to other languages as well.
