We don't have support for RTL languages yet.

Why did not do this yet. We are tired of waiting for this, do you know the number of Arabic speakers and also the rest of the right-to-left languages​​.

Well if you do not mind reading on the progress. Note that Bugzilla is Not a discussion forum like here so please no "Why" comments in any of the bugs. Also Bugzilla etiquette

Bug 702845 - [meta] RTL support for Firefox for Android