IBM has donated translations from their products to Eclipse.
The language pack is distributed as a feature which you can
install by downloading the zip file, unzipping it into your
Eclipse directory and restarting Eclipse. This language pack
contains translations for German, Spanish, French, Italian,
Japanese, Korean, Portuguese (Brazil), Traditional Chinese,
Simplified Chinese, Czech, Hungarian, Polish and Russian,
and Arabic.

WWW: http://download.eclipse.org/eclipse/downloads/drops/L-3.1.1_Language_Packs-200510051300/index.php