The Arabic language family is divided into several categories which are: Old Arabic, the literary varieties, and the modern vernaculars.^[1]

The genealogical position of Arabic within the group of the Semitic languages has long been a problem.^[2]

Semitic languages were confined in a relatively small geographic area (Greater Syria, Mesopotamia and the Arabian desert) and often spoken in contiguous regions. Permanent contacts between the speakers of these languages facilitated borrowing between them. Borrowing disrupts historical processes of change and makes it difficult to reconstruct the genealogy of languages.^[3]

In the traditional classification of the Semitic languages, Arabic was in the Southwest Semitic group, based on some affinities with Modern South Arabian and Geʽez.^[4]

Most scholars reject the Southwest Semitic subgrouping because it is not supported by any innovations and because shared features with South Arabian and Ethiopic were only due to areal diffusion.^[5]

In 1976, linguist Robert Hetzron classified Arabic languages as a Central Semitic language:^[6]

John Huehnergard, Aaron D. Rubin, and other scholars suggested subsequent modifications to Hetzron's model:^[7]

However, several scholars, such as Giovanni Garbini, consider that the historical–genetic interpretation is not a satisfactory way of representing the development of the Semitic languages (contrary to Indo-European languages, which spread over a wide area and were usually isolated from each other).^[8] Edward Ullendorff even thinks it is impossible to establish any genetic hierarchy between Semitic languages.^[6] These scholars prefer a purely typological–geographical approach without any claim to a historical derivation.^[4]

For instance, in Garbini's view, the Syrian Desert was the core area of the Semitic languages where innovations came from. This region had contacts between sedentary settlements—on the desert fringe—and nomads from the desert. Some nomads joined settlements, while some settlers became isolated nomads ("Bedouinisation"). According to Garbini, this constant alternation explains how innovations spread from Syria into other areas.^[9] Isolated nomads progressively spread southwards and reached South Arabia, where the South Arabian language was spoken. They established linguistic contacts back and forth between Syria and South Arabia and their languages. That is why Garbini considers that Arabic does not belong exclusively to either the Northwest Semitic languages (Aramaic, Phoenician, Hebrew, etc.) or the South Semitic languages (Modern South Arabian, Geʽez, etc.) but that it was affected by innovations in both groups.^[10]

There is still no consensus regarding the exact position of Arabic within Semitic languages. The only consensus among scholars is that Arabic varieties exhibit common features with both the South (South Arabian, Ethiopic) and the North (Canaanite, Aramaic) Semitic languages, and that it also contains unique innovations.^[10]

There is no consensus among scholars whether Arabic diglossia (between Classical Arabic, also called "Old Arabic" and Arabic vernaculars, also called "New Arabic" or "Neo-Arabic") was the result of the Islamic conquests and due to the influence of non-Arabic languages or whether it was already the natural state in 7th-century Arabia (which means that both types coexisted in the pre-Islamic period).^[11][12][13]

According to Dutch linguist Kees Versteegh, modern vernaculars (also called dialects, colloquial varieties or spoken Arabic varieties) are classified as follows:^{[14][lower-alpha 1][lower-alpha 2]}

• Arab (disambiguation)
• Etymology of Arab
• Varieties of Arabic