Other languages are available for shared accounts; just go to cPanel and click Change Language.
Resellers have the RVSkins feature by default. Simply go to WHM and click Create a New Account. Under Settings, you will see multiple languages available in a drop down.
RVSkins for VPS and dedicated servers can be ordered at this link. The cost is $60 a year and includes installation.
Official Links
RVSkin supported languages.RVSkin themes can be viewed here.