Actually I'm in Middle East (KSA) And the game itself it not available anymore in store!! By this reason I changed my location to Germany to download it. Since Purchase time I couldn't found the arabic languag and the subtitle that I'm using now is English. And in store there is (FR & PL). There is no (AR) just in PC.
Just change your Xbox country to United Arab Emirates from settings, uninstall the game and reinstall it and your problem should be solved. The Arabic subtitle and menu will be available in game's settings