Here we will discuss some structural features of Arabic dialects, including the pre-Classical variety, which resemble different Semitic languages, both in the same branch and in different branches. Classical/Modern Standard Arabic is typologically unique because it contains features that are different from both the epigraphic data in the Arabian Peninsula and also from the modern spoken varieties of the language in the Middle East and North Africa. This typological 4 difference among varieties of Arabic introduces the question of the position of the language in the Semitic family from a genealogical point of view and also from the point of view of it being a language that developed subcategories or different dialects that, for non-linguistic reasons, came to be realized as a language.
One of the features that is traditionally claimed to set Arabic apart from the rest of the Semitic languages is the preservation of the initial w in words. While this feature is common among all the varieties of Arabic and while it sets Arabic apart from North West Semitic, it exists in Akkadian and the South East Semitic varieties of Ethiopia. It also exists in the Semitic varieties in the Arabian Peninsula. The Arabic refl ex of the Semitic sibilants also sheds light on the position of the language among its Semitic family. The refl ex of the Semitic s1 in Arabic is /s/ exactly as s3. But s2 appears in Arabic as a /š/. This treatment sets Arabic apart from all the North Semitic languages including Akkadian, Ugaritic, Hebrew and Aramaic. But Ge‘ez and the other ancient languages of the peninsula treat the sibilants in the same manner as Arabic. A third sound phenomenon that is sometimes claimed to be distinctive of Arabic is the so-called emphatic consonants. Their origin and real sound quality in Arabic is not clear. It is claimed that it used to have an ejective quality in the pre-Classical and Classical periods. It is, on the other hand, claimed to be a synharmonic phenomenon, in which the consonants and the neighboring vowels suffer backing in the place of articulation. Some of the modern dialects, especially in Yemen, exhibit an ejective quality, while the rest of the modern dialects of Arabic show the synharmony phenomenon.
There is another relevant sound phenomenon, which is interesting for our purpose here, because it links Arabic to the Northern Semitic group. The interdentals in Classical/Modern Standard Arabic and in some typologically Bedouin dialects are also indicative of the position of Arabic among the Semitic languages. Although in the previous phenomena the Arabic language differed from members of the Northern Semitic languages, the /ṯ/ and /ḏ/ exist at least in Ugaritic. These two sounds are, however, absent from the majority of the modern dialects of Arabic. Arabic is not only related to the Ethiopic group by the persistence of the initial w, but also by the morphological phenomenon of the broken plurals (Palmer 1962: 16–34). However, the relationship between broken plurals in the pre-Classical/Classical/ Modern Standard Arabic and the modern dialects is not quite clear. The difference in formal forms and the functions of each form are still issues that need corpus-based work and further synaptic/semantic investigation.