Hi
Kindly i suggest to use saudi Arabia flag as an icon for Arabic language for the following reason
1- the modern standard Arabic language is based in quran which spread from hejaz region now the main part from Saudi arabia .
Saudi arabia is the biggest country in Arabian peninsula the hartland of Arabic languag and people .
All muslims around the world know the Saudi Arabia flag . Most people they didn’t recognize the arab league flag which is an political organization like UN