Ẓāʾ

In Classical Arabic, it represents a velarized voiced dental fricative [ðˠ], and in Modern Standard Arabic, it can also be a pharyngealized voiced dental [ðˤ] or alveolar [zˤ] fricative.

In most Arabic vernaculars ظ ẓāʾ and ض ḍād merged quite early.^[1] The outcome depends on the dialect. In those varieties (such as Egyptian, Levantine and Hejazi), where the dental fricatives /θ/ and /ð/ are merged with the dental stops /t/ and /d/, ẓādʾ is pronounced /dˤ/ or /zˤ/ depending on the word; e.g. ظِل is pronounced /dˤɪl/ but ظاهِر is pronounced /zˤaːhɪr/, In loanwords from Classical Arabic ẓāʾ is often /zˤ/, e.g. Egyptian ʿaẓīm (< Classical عظيم ʿaḏ̣īm) "great".^[1][2][3]

In the varieties (such as Bedouin and Iraqi), where the dental fricatives are preserved, both ḍād and ẓāʾ are pronounced /ðˤ/.^[1][2][4][5] However, there are dialects in South Arabia and in Mauritania where both the letters are kept different but not consistently.^[1]

A "de-emphaticized" pronunciation of both letters in the form of the plain /z/ entered into other non-Arabic languages such as Persian, Urdu, Turkish.