Arabic dialects are normally divided into several geographical units: Western or Maghrebinian dialects (Morocco, Algeria, Tunisia, and Libya), Sahel Arabic (Chad and Sudan), Egyptian Arabic, Levantine Arabic (Palestine, Syria, Lebanon, Jordan), Mesopotamian Arabic (Iraq and western Iran), and the dialects of the Arabian Peninsula. Each of these dialect groups is divided into regional sub-groups, which in turn include many local dialects. In most Arabic-speaking countries there is a general distinction between urban and rural dialects, and often between the dialects of settled and formerly nomadic (Bedouin) populations. Distinct local varieties are often spoken by different religious communities.
Arabic dialects can be classified based on certain phonological, morphological and syntactic features, as well as their considerable lexical variation. Whether these features render dialects as mutually intelligible or unintelligible is open to debate, but in general, dialects are mutually intelligible, with exceptions occurring on the periphery of the Arabic-speaking world. Sedentary dialects are viewed as being less isolated from other languages, whilst more conservative Bedouin dialects display features hat are more akin to those found in Classical Arabic. However, this view is somewhat misleading, especially in the Arabian Peninsula where most dialects preserve archaic features. In reality, the boundaries between these two ‘lifestyles’ are often blurred.
Phonological variation is evident in key phonemes. The /q/ phoneme has several reflexes (q, g, k/ḳ, ǧ/dz,ʔ), as does /ǧ/ (ǧ, g, ɟ, ž) and /k/ (k, č). The interdentals /θ/ and /ð/ may be realized as the stops /t/ and /d/ respectively. Similarly, there is contrast in consonant clustering and syllabification patterns, and the resulting absence/presence of epenthetic vowels. All these variations can be used generally to differentiate dialects as urban or rural, or to connect dialects that share the same features. In the latter case, this can often reveal links between dialects that are geographically distant. For example, word stress, where some communities in southern Oman, the Negev, Libya (Cyrenaica) and Morocco differ from the rest of the Arabic-speaking world through their use of an iambic stress pattern.
Morphologically, there are two genders. In some dialects, mainly urban, gender is not differentiated in second and third person plural pronouns, as well as verbs, with the masculine form is used as default. Where the feminine gender distinction remains in plural pronouns and verbs, then it is also present in demonstrative plural pronouns. Both genders may also occur in the first person singular pronouns of some Yemeni dialects.
Syntax variation is generally more identifiable on a geographical basis. In some Iraqi and peripheral eastern dialects, word order and the presence of a copula reflects the influence of neighbouring languages. Here, the use of an indefinite article can also be found, as is also the case in the western dialects such as Morocco, Mauritania and Algeria. Such grammaticalised features are common, and a great deal of variation can be found in the synchronic use of function words and their diachronic development (tense/aspect verbal prefixes and auxiliaries, adverbs, possessive linkers, conjunctions, indefinite articles and inceptive verbs).