I wanted to point out an important detail in my blog post AutoCAD 2010 Language Packs German and French Available
You can only install within language families currently. This means that customers in the Americas are not able to download a Japanese language pack and customers in Japan are not able to download Traditional Chinese. Currently there is no EMEA European subscription customer support for language packs.
Language Families:
Americas
English, French, Italian, German, Spanish and Brazilian PortugueseJapan
English, JapaneseChinese and Korean Asian Markets
English, Korean, Simplified Chinese, Traditional Chinese
Cheers,
Shaan