Another separate Semitic family once spoken in the region is Old South Arabian; these became extinct in the pre-Islamic period with the possible exceptions of Razihi and Faifi.
Grammatically, all Tihami dialects also share the unusual feature of replacing the definite article (al-) with the prefix (am-).
The future tense, much as in the dialects surrounding Sana'a, is indicated with the prefix (š-) for all persons, e.g. šabūk am-sūq "I shall go to the market”.
It shares the transformed definite article of (am-) originally used in Himyaritic with the rest of the Tihami dialects, but it is unique in retaining certain of the declensional suffixes in the nominative case.
Likewise the phonology of the Zabidi sub-dialect replaces the sound (ʿain) [ʕ] (ع) with the glottal stop ( ʾ ) [ʔ] (ء).
The Hadhrami dialect in many towns and villages in the Wādī (valley) and the coastal region is characterised by its pronunciation of the voiced palatal plosive (or affricate) (ج) as the semi-vowel (ي) (y) ([j]).
In educated speech (ج) is realised as a voiced palatal implosive ([ʄ]) or affricate ([dʒ]) in some lexical items.
With the spread of literacy and contact with speakers of other Arabic dialects, future sociolinguistic research may reveal whether HA is going to witness innovation such as using the uvular /q/ in certain lexemes while retaining the velar /ɡ/ for others.
Wādī HA makes ث / ت [t], [θ] (⟨t⟩, ⟨ṯ⟩) and ذ / د [d], [ð] (⟨d⟩, ⟨ḏ⟩) distinction but ض (Classical Arabic /ɮˤ/) ⟨ḍ⟩ and ظ [ðˤ] ⟨đ̣⟩ are both pronounced ظ [ðˤ] whereas Coastal HA merges all these pairs into the stops د , ت and ض (/t/, /d/ and /ḍ/) respectively.
The effect of Hadrami migration to Southeast Asia (see Arab Singaporeans), the Indian subcontinent and East Africa on HA is clear in the vocabulary especially in certain registers such as types of food and dress, e.g. (ṣārūn) "sarong".
Along with the southern bedouin dialects, in Abyan and Lahej, with which it shares much in common, Yafi'i pronounces the classical jīm (ج) as gīm, but unlike all other dialects, Yafi'i systematically pronounces the classical sound ġayn (/ʁ/) as qain and qāf as ġāf, effectively switching the pronunciation of one letter for the other.
Whereas the shift is systematic in Yafi', occurring at every instance of the relevant phonemes, in Sudan, it is usually a form of hypercorrection that takes place only in certain classical words.