Why do not you want to add the Arabic language for the program?
Many arab users use it and you don't want to add arabic language This racist
Opaite Mbohovái (1)
Do you always accuse people of being racist if you can't find something? Maybe the problem is you didn't ask where to find it.
Of course there are Arabic-language localizations of Firefox for both desktop operating systems (https://www.mozilla.org/firefox/all/) and for Android.
Where have you been looking -- which Google Play store do you use?
If your Google Play store doesn't offer Firefox for Android in Arabic, it could be because your device is not compatible. But if you want to try "sideloading" it, you can find the APK's here:
http://ftp.mozilla.org/pub/mozilla.org/mobile/releases/latest/android-api-11/ar/ (Android 3.x-5.x, I think)
http://ftp.mozilla.org/pub/mozilla.org/mobile/releases/latest/android-api-9/ar/ (Android 2.3, I think)
Does it work?