Screenshot

About
This script was originally created for the JLU (Japanese Language and Usage) site as part of the Creating as much Japanese interface as possible to be more inclusive of native Japanese speakers meta page, but it now should work on all the major Stack Exchange sites.
To change to Japanese, click the 日本語版 icon which will appear in the top right corner of every page.
It's a work in progress, but a reasonable amount of the site has been translated including UI elements, tooltips, dates, some messages, Stack Exchange badges+descriptions, tags on the JLU site etc. For the current status, please see the about page at userscripts.org.
I'm not a Japanese native speaker and there are lots of errors. If anyone could give any assistance correcting or contributing to the translation I'd much appreciate it.
License
CC-BY-SA
Download
- Download from: http://userscripts.org/scripts/show/122087
- How to install this user script: http://stackapps.com/tags/script/info
Platform
The platforms I'm currently testing it on are Firefox 9.0.1 with Greasemonkey and Google Chrome "16.0.912.75 m". I intend to support IE, Safari and Opera soon.
Contact
Please leave a comment or post an answer here and I'll try to respond as quickly as possible.
Code
It uses jQuery/JavaScript.
The source code can be viewed at http://userscripts.org/scripts/review/122087.