Ancient North Arabian
In the western two-thirds of the Arabian Peninsula, from southern Syria to Yemen, inscriptions testify to the use of a number of different ancient languages and scripts. In the southwest, these inscriptions may date from as early as the thirteenth century BC and continue up to the seventh century AD, while in central and north Arabia they seem to be concentrated in the period between the eighth century BC and the fourth century AD. Some languages, like Aramaic and, later, Greek, came to the region from outside, but the rest were indigenous tongues expressed in scripts developed locally.
Literacy seems to have been extraordinarily widespread, not only among the settled populations but also among the nomads. Indeed, the scores of thousands of grafﬁti on the rocks of the Syro-Arabian desert suggest that it must have been almost universal among the latter. By the Roman period, it is probable that a higher proportion of the population in this region was functionally literate than in any other area of the ancient world.
The Cambridge Encyclopedia of the World’s Ancient Languages, edited by Roger D. Woodard (Cambridge University Press. 2004)