The texts on this site will appear in the language you type them in.
اذا آردت آن تكتب نص باللغة العربية فما عليك الا ان تسدخدم
your Arabic keyboard.
To communicate in an international language, usually people select English to be best understood by the majority of internet users. Also because they are used to doing so.
As for the main navigation of this site, it needs to be translated. I could use some tips on how to word things (need to use cool arabic text not classical stuff when possible).