This probably has several levels:

Card Keys

currently one major problem:

1. based on pluralization (need to be able to turn this off) - add setting for pluralization

Content

It looks to me like international content basically works, but sometimes (as in inclusion and probably links) content is breaking largely because of unicode characters getting treated as html entities.  We may be able to change this behavior by messing with this TinyMCE setting (they've changed their dosc infrastructure, probly need new link):

http://wiki.moxiecode.com/index.php/TinyMCE:Configuration/entities

Changing the default language

(i.e. translated controls, etc.)

There are several things to do here:

1. moving all english out of the code (and into cards), including all the warning messages - move cue text to editable cards

2. codenames - so that even Star Cards names may be changed (all star cards, not just builtins -- which are going to disappear --efm)

3. pushing sites like en.dwagn.org further so that they may be created for multiple languages - Wagneer English to be ready for other languages

4. hands and such to separate structure from language - add ability to pass hands of cards between Wagns

Multi-lingual support

- present different content based on user's language setting

yeah, this one is hard :)