I wonder whether there was a greater concentration of Chalcedonians in Eastern Syria, and whether Arabization was greater in these areas, since there are still villages where even the Muslims have retained this old dialect of Aramaic.
I wonder if the Chalcedonians would have been increasingly in the western areas over time.
If I remember correctly when the Crusaders arrived in these areas in the 11th century many of the Christians from Syria down through Lebanon and the Holy Land were still Chalcedonian & Byzantine in mentality with their own Patriarchs still in Antioch & Jerusalem (this last is often forgotten in the accounts of the Crusaders who had to interact with the Christian populations they encountered along their way to Jerusalem. At first they respected the fact that these were separate Patriachates but then they replaced them with Latin patriarchs directly subordinate to the Pope). I don't remember though the languages these local Christians spoke who were found in all the major cities & villages along the way to Jerusalem. Just on a guess- Greek in the cities, Aramaic in the villages.
In any case I was able to find this interesting comment about St Issac in the Introduction the Holy Transfiguration version of his homilies:
After noting that St Isaac originally came from the area now known as Qatar when he was made bishop of Nineveh, the Intro comments about why he may have retired as bishop:
It is certain that the citizens of Nineveh were displeased to have a foreigner as their bishop. ...The appointment of Saint Isaac, who came from the distant, uncivilized region of Qatar...must have been regarded by the Ninevites with the utmost displeasure. At that time Nineveh and its environs, being near the Jacobite stronghold, the monastery of Mar Matta, was a centre of Monophysite activity. Continuous and vehement doctrinal dispute plagued the city, and the loyal sons of the Persian Church [who were Nestorians] must have expected Saint Isaac to champion their cause... We know, however, from the saint's writings the dislike he had for disputation... such actions, could have been misinterpreted, especially by narrow-minded persons. If, as bishop, Saint Isaac remained as silent on christological issues as he does in his Homilies, many suspicions would have arisen. There is no indication, for instance, that he accepted the christological formula which confesses two hypostases in Christ. If he did not state himself clearly about this, the extremists in his flock would have charged him with crypto-Monophysitism.
In Christ- Fr Raphael