Could you find a scientific answer to that question in the title? It took me over an hour, and I didn’t actually find an answer, but I did find quite a bit of literature on the subject. Remember, I don’t have a linguistic background and I had never thought about Arabic accents before.
This is one of the beauties of my job. Anyone can come along with any subject (as long as it’s humanities) and I have to help them find something to help them with their research. Often the students already have an idea about where to look, but are uncertain that they are doing the right thing. These are smart people, who just need a nudge in the right direction.
But it also gives me the chance to learn something about a subject I would never even consider. And I ‘found’ a resource, hidden in plain sight, which was very good: The Encyclopedia of Arabic language and linguistics, which reminded me once again that encyclopedias are very useful for research.