You can add additional languages to the Mac OS X default language list by clicking the Edit button in the International pane of System Preferences, and then selecting any language checkbox in the resulting dialog.
iDVD 5 supports the following languages: English, Japanese, French, German, Dutch, Italian, Spanish, French Canadian, Simplied Chinese, Korean, Traditional Chinese, Swedish, Danish, Norwegian, and Finnish.
If you move a language that iDVD does not support to the top of the Languages list and then either logout and login or restart your computer, iDVD may unexpectedly quit when you use it to burn a project to DVD or save a project as a disc image. This can occur with Mac OS X 10.3 or later.
To resolve this issue, make sure that the language at the top of the Language list in the International pane of System Preferences matches one of the supported languages when you burn iDVD projects. If it doesn't, drag one of the supported languages to the top of the list, burn your project, and then move your chosen language back to the top.
You will need to logout and login or restart the computer before trying iDVD again.This document will be updated as more information becomes available.