TuxMath 1.6.0 has been released, featuring native language support on Windows as well as Linux/Unix. Supported languages include French, Dutch, Norwegian Bokmal, Norwegian Nynorsk, and Czech (and new translations can be very easily added).
There is also a passwordless login in the Linux build for keeping track of individual students' progress in a classroom setting, as well as a command-line admin utility, "tuxmathadmin".
If you wish to contribute a translation, all you need to do is to create a .po file for your language based on the template file "po/tuxmath.pot" in the source tree. Email us at tuxmath-devel@lists.sourceforge.net for further info.