[luckylion]

That's true, but I don't know if Slavs are comparable to Arabs. There are different Slavic ethnic groups with very distinct languages. Arabs are one ethnic group with one language, but part of the Semitic family.

I suppose the Sunni/Shia conflict has an ethnic component with the Persians mostly being Shiites, while most Arabs are Sunni.

[jacobush]

Not convinced. According to arabs I know, they hardly understand each other at all if they are from to far away countries and never learned the "formal" form.