Gingerbread Claims Support for Arabic, but I Don't See the Language in Settings
Where do you live, what's your carrier, and how did you upgrade to 2.3.4?  Normally US firmware won't have Arabic, for example, since it would be wasting space on 99% of people's phones in the US.

That doesn't mean you can't add it.  I think this page provides a method for doing it, but I can't read Arabic :P