I've responded to questions about language packs for Reader several times recently so I thought I'd post an entry about it. These files have beep posted since July 2008 but if you're not monitoring the Downloads pages for Reader, you may not have noticed. For future reference, you might want to bookmark...

Downloads for Adobe Reader
Windows | Macintosh

There are two separate functions that the language packs offer:

1. A supplemental dictionary that lets you spell check in all 32 languages that Reader supports and...
2. Font packs that let you view, comment or fill in fields on documents authored in other languages where the author did not embed the appropriate font.

You can download the dictionary and font packs at the links below.

Adobe Reader 9 Spelling Dictionary Pack
Windows | Macintosh

Adobe Reader 9 Font Packs - Japanese
Windows | Macintosh

Adobe Reader 9 Font Packs - Korean
Windows | Macintosh

Adobe Reader 9 Font Packs - Chinese Traditional
Windows | Macintosh

Adobe Reader 9 Font Packs - Chinese Simplified
Windows | Macintosh

Adobe Reader 9 Extended Language Font Packs (including Chinese Simplified, Chinese Traditional, Korean and Japanese)
Windows | Macintosh