Thank you very much mph!

We just added this files in 1.0.2. It's already available on wordpress.org plugin directory.

Hello, 

I want to build a bilingual forum with an English and a German part. 

Can the user select the language when registering and then his menu will always be in German? 

Thank you!

If your Multi Language plugin support Multi-language menus you can make two language menus in Dashboard > Appearance > Menus admin page. wpForo menu is a regular WordPress menu. Please read the doc: https://wpforo.com/docs/root/getting-started/forum-menu/