Ave - RTL

To use the RTL feature, you need to open up your wp-config.php and add the following:

define ('WPLANG', 'ar'); 
like this:
In this case, “ar” refers to the Arabic language. Check out the full list of ISO language codes.
Then hop on over to Settings -> General -> Site Language – and select your language.

You can also use plugins like RTL Tester.