Bug 83941 “bzr doesn’t speak my tongue” has been closed: bzr core can now be translated. (The qbzr and bzr-explorer guis have been internationalized for a couple of years.) If you want to help bring bzr to those who prefer to work in non-English languages please help translate at Launchpad.
The translation will involve quite a bit of specialist language (what is French for “colocated branch”?) and I expect there are strings yet that need to be added to the translation file. I also need to look at translations for plugins. Please send issues to either the Bazaar mailing list or as bugs on bzr on Launchpad.
Philippe Lhoste wrote a while ago about the issues of translating DVCS terminology.