I don't know anything about Arabic language games specifically, but in general localization costs on games (especially ones with a lot of text) can be quite high, so it mostly boils down to "will we sell enough copies of the game in that region to cover our localizing costs?" 

If it doesn't look like we sell enough units in that region, our hope is that local fans also speak one of the languages we do translate the games into (those being Japanese, English, French, Spanish, German, and Italian).

best,

Seth