Could I make a language branch?

I’m from Brazil, and i’m learning about jME, i want to know, if could I make a “jME Brasil” forum, site, wiki, for the brazilian developers. To apply my future knowledge on these. Could I? I need a permission for this? What i have to do? Anyway, THANKS!

Nothing will prevent you from doing that.

Whether it’s a good idea is an entirely different question - you reach more people locally, but they won’t reach the international JME user community that easily.
Most gaming literature is in English anyway, so your community will be tend to collect those who have limited access to gaming-related knowledge.

If you add brazilian wiki pages, just make them the same name as the original and add _br at the end, e.g. jme3:custom_meshes_br