In the aftermath of the Neklë, the Great Levantine Dispersion (1918-2068), the lingua franca al-ʻarabiyyah al-fuṣḥa fell out of use. The Arabic languages jockeyed for cultural hegemony, though they tended to be confined to certain domains outside of their localities. Gulf Arabic prevailed in the business world, while Egyptian Arabic dominated the airwaves in television and film, though its share of the market waned rapidly. Moroccan Arabic had geographic dominance over northern Africa and western Europe.
The Arab Levant had been left devastated and unable to compete with the rest of the Arab world, and most of its population was scattered in diaspora. It turned out that this was precisely what led to its later status as the dominant Arab language. Prevented from assimilating, Palestinians and Syrians especially retained the dialects of their homelands. They were generally highly educated, often skilled, and well-networked, making them upwardly mobile when the opportunity was present.
Over time, the other dialects gave way to the Levantine dialect, though the Bedouin dialects stuck around. Having achieved hegemony among the Arabs, the language of the disenfranchised among the Arabs was ironically commanding one of the largest and most powerful language communities on the planet.
Ajam is its direct descendant.
In progress . . .