What present-day diglossia in Arabic inscriptions can tell us about the linguistic situation in the early Islamic period

This article compares modern and early Islamic Arabic graffiti from the Syro-Arabian Ḥarrah (Black Desert) and the Ḥismà to investigate the relationship between literacy, diglossia, and orthography. Modern inscriptions, written by individuals with rudimentary education in Modern Standard/Classical Arabic, exhibit pervasive grammatical and spelling irregularities, including phonetic spellings and code-switching, which reflect the significant linguistic distance (diglossia) between the written high register and the spoken vernacular. These orthographic irregularities are nearly absent in early Islamic graffiti from the Ḥismà, where deviations from Classical Arabic are instead systematic and rule-bound. This situation is the result of “orthographic depth”, indicating that the early Arabic script was standardized within a scribal educational context, not a near-phonetic environment like Safaitic, and suggests a shallower diglossic gap or a higher degree of scribal regulation in the early Islamic period.