I looked everywhere for Arabic Language or firmware, but didn’t find! I’ve only found an Arabic keyboard, but it doesn’t change display language.
i think you have to go to nokia care, if it is not covered by warranty then this will coast (you can check with them), also i think if you hard reset or update firmware language will revert to initial state so you will have to restart all over again. This is because the phone was not destined for Arab countries.
nokia lumia 610 arabic