I've written a patch to turn the mooix MOO into a multilingual MOO. As far as I know, this is the first fully multilingual MUD in existence.
This patch is the result of my work making mooix multilingual. It is twenty seven *thousand* lines. It assumes my VServer patch.
I also have a subversion server set up that holds this data, but Joey has never responded to my repeated queries as to whether he was OK with me releasing that server's address to the community.
It allows allows multiple users to communicate with the same mooix session at the same time in different languages, without ever seeing any language but their own unless that language is being spoken (via the "say" command or similar) by another user.
This is, the two different users will be typing different commands in different languages, and seeing different languages (but hopefully the same semantic content!) in the output.
Example runs are at the English test script and the Lojban test script
These two scripts (the first in English and the second in Lojban) each have their users doing exactly the same actions, in effect, but with totally different results. Note that unless each specifically asks for the other language, the English user never sees Lojban, and vice versa.
It does not provide for an optimal ease-of-use strategy WRT maintaining and creating translated objects.