I will run it in my language, not in english.
As you can read at the bottom of every page, this forum is based on SMF (Simple Machines Forum).
Give a look at http://www.simplemachines.org/ for further information.
I've never used SMF personally, but I've used it in several places and it's always worked well from a user's perspective. If I ever create a forum for something, it's probably what I'll use. Keep in mind though that this forum is heavily modified from the default configuration, and you'll want to use the latest version (currently 2.0.8 ) for security.