I purchased the WikiReader, one for myself, and one for my granddaughter's school work. It's great for a quick check of information while I'm in front of the TV (which is where I keep it)
Anyway the site has the entire wikipedia information where you can download it. Lots of open source files and "how to" get other wiki's. If you can figure it out and translate it, it's there, free for download.
The main site is http://thewikireader.com/
this is another site for the developments.
Unfortunately, all the developement is beyond my programming skills which stopped at Basic (the old DOS days....)