Another option is a true multilingual wiki -- one site where the various pages, or even various parts of the same page use different languages. The benefit for multilingual users is that they can search for information in other languages easily. The drawback for monolingual users is that many pages listed on RecentChanges are not usable.
Worth scanning to see how the rest of the world is adapting to multilingualness is JournalOfComputerMediatedCommunication, [vol.9(1)] special issue on multilingual issues.
CategoryWikiTechnology CategoryGlobalization CategoryUncommonWikiTechnology