Updated Language Packs for users using Windows Vista SP1 as well as those running Windows Vista RTM. For those running SP1, the Language Packs should be showing up for you under Windows Update. The specific language packs which are being released are as follows:

• German
• English
• Spanish
• French
• Japanese
• Korean
• Bulgarian
• Czech
• Danish
• Greek
• Estonian
• Finnish
• Hungarian
• Italian
• Lithuanian
• Latvian
• Norwegian
• Dutch
• Polish
• Portuguese (Portugal)
• Romanian
• Slovak
• Slovenian
• Swedish
• Arabic
• Hebrew
• Croatian
• Portuguese (Brazil)
• Serbian (Latin)
• Thai
• Turkish
• Ukrainian
• Chinese (Simplified)
• Chinese (Traditional)
• Russian

More info….

Source:→ Windows Vista Team Blog

Windows Vista, Language Packs