Tom Gewecke, owner of Multilingual Mac a site dedicated to share info about using non-English languages on the Mac, has posted about the iPad’s support for non-English languages.
In particular there is no input for Greek, Arabic, Hebrew, Traditional Chinese, and also various European languages. iPad Safari can display all of these without problem.
iPad Language Capabilities Update [Multilingual Mac].
Arabic version of this post on SaudiMac.net.