You may form a team from representatives of your nation and use almost any language at forums. These forums will be publicly visible, but only your team members will be able to make posts therein.
In the beginning there were much more players from The Netherlands on lidraughts than other nationalities, so this made most sense to add as a forum category. Today the crowd is much more international, but we can't add forums for all languages... Creating a team for that is a nice suggestion by kalnap