Hejazi Arabic phonology

The phonological system of the Hejazi Arabic consists of approximately 26 to 28 native consonant phonemes and 8 vowel phonemes: , in addition to 2 diphthongs: . Consonant length and vowel length are both distinctive in Hejazi.
Strictly speaking, there are two main groups of dialects spoken in the Hejaz region, one by the urban population "" originally spoken in the cities of Jeddah, Medina and Mecca where they constitute the majority and partially in Ta'if, and another dialect spoken by the Bedouin or rural populations which is also currently spoken as well in the mentioned cities. However, the term most often applies to the urban variety which is discussed in this article.
Consonants.
Hejazi consonant inventory depends on the speaker. Most speakers use 26 consonants with no interdental phonemes or 28 phonemes, with the phonemes and being used partially due to the influence of Modern Standard Arabic and neighboring dialects, in addition to the marginal phoneme and two foreign phonemes ⟨پ⟩ and ⟨ڤ⟩ used by a number of speakers. Being a Semitic language, the four emphatic consonants are treated as separate phonemes from their plain counterparts.
Phonetic notes:
A notable feature of Hejazi is the pronunciation of as in Modern Standard Arabic. It is pronounced as which differentiates it from other dialects in the Arabian Peninsula that merge the phoneme into . Another feature which is shared by many Arabic dialects is the pronunciation of as a voiced velar , which Ibn Khaldun states may have been the Old Arabic pronunciation of the letter. He has also noted that Quraysh and the Islamic prophet Muhammad may have had the pronunciation instead of . Due to the influence of Modern Standard Arabic in the 20th century, has been introduced as an allophone of in a few words borrowed from Modern Standard Arabic, such as ('economy'), which can be pronounced or , or religious terms as in ('Quran') which can be pronounced as by younger speakers or by older speakers. The two allophones might contrast for a number of speakers, e.g. ('horns') vs. ('centuries') which might suggest as a marginal phoneme.
Glottal Stop.
The glottal stop was lost early on in the Old Hejazi Arabic period. This can be seen in Modern Hejazi as in "they read" and "diagonal" vs. Classical Arabic and . In the initial position, the glottal stop's phonemic value is debatable and most words that begin with a glottal stop according to Classical Arabic orthography can be analyzed as beginning with a vowel rather than a glottal stop. For example, "bracelet" can be analyzed as or and "I eat" analyzed as or , but it is still phonemic and distinguished in medial and final positions and distinguished as such in words, as in "he asks" or words under the influence of Modern Standard Arabic such as "environment" and "administrator, responsible".
Gemination.
Long (geminate or double) consonants are pronounced exactly like short consonants; they occur between vowels and they are marked with a shaddah if needed, e.g. كَتَّب or "kattab" "he made (someone) write" vs. كَتَب "katab" "he wrote". They can also occur phonemically at the end of words but are pronounced as a single consonant, not geminated, e.g. فَمّ ('mouth') which is pronounced with a single final consonant .
Assimilation.
Consonant assimilation is a phonological process which can occur between two consecutive consonants as in before as in 'next to' → or , or between dental consonants; before as in 'next to' → , or before as in 'next to' → , before as in 'I enjoyed it' → which is differentiated from "he was flattened / he enjoyed" by the stress, in the former the stress falls on the last syllable while on the latter it falls on the first.
Dental Assimilation.
Notes:
The Classical Arabic phoneme came to be pronounced as in 'gold' or as in 'he studied', on the other hand is mostly pronounced as in 'bull' or rarely as in 'stable'. is pronounced distinctly as in 'phenomenon' or merges with in other words like 'dark' and 'nail'. In contrast is always pronounced as a except in words derived from the two trilateral roots and in which it is pronounced .
Mergers depend on each word, while most words have only one pronunciation, few words have two optional mergers e.g. كذب might be pronounced as by some speakers or by others. The partial merger between the phonemes has led to some homophones that did not exist in Modern Standard Arabic e.g. 'dimming' and 'mislead' both pronounced , while the assimilation of the word (second; number-two or unit of time) has made a split into two pronunciations (words) (second; number-two) and (second; unit of time).
The use of spelling pronunciation depends on the speaker; for example, many might refrain from the usage of as a pronunciation for and only merge with in most words while keeping in others. This phenomenon might be due to the influence of Modern Standard Arabic and neighboring dialects. When speaking or reading Modern Standard Arabic, Hejazi speakers pronounce each consonant distinctly according to its modern standard phonemic value, and any mergers such as the merge between and can be stigmatized.
Vowels.
Hejazi has eight vowel phonemes: three short , , and five long , , , and , with length as a distinctive feature, and two diphthongs: and . Unlike other Arabic dialects, it did not develop allophones for the vowels and in the vicinity of emphatic consonants, and they are always pronounced as an open front or open central depending on the speaker. Hejazi also retains most of the long and short vowels of Classical Arabic with no vowel reduction, although in a few words and are pronounced with an open back .
The main phonological feature that differentiates urban Hejazi from the neighboring dialects of the Arabian peninsula and the Levant is the constant use of full vowels and absence of vowel reduction (use of the schwa ). For example 'I told you' (to a female), is pronounced or in Hejazi with full vowels but pronounced with the reduced vowel as in most of the Gulf region or in Lebanese and urban Syrian. It also retains the Classical mid breaking vowels as in ("your dauɡhters") in Hejazi as opposed to or in Egyptian and Najdi and rural Hejazi.
Most inherited words with the two diphthongs and from the Old Arabic period underwent monophthongization in Hejazi and are realized as the long vowels and respectively. However, they are still preserved in many words such as 'animal', and have resurfaced in a number of words borrowed later from Modern Standard Arabic. This created a contrast with the inherited monophthongized words as in "inherited" 'my voice' vs. "borrowed" 'acoustic', and "inherited" 'my eye' vs. "borrowed" 'ophthalmic'. Not all instances of mid vowels are a result of monophthongization — some are from grammatical processes 'they said' → 'they said to her' (opposed to Classical Arabic ), and some occur in portmanteau words e.g. 'why?' (from Classical Arabic 'for what' and 'thing'). 
The pronunciation of word initial and medial and depends on the nature of the surrounding consonants, whether the syllable is stressed or unstressed, the accent of the speaker, and rate of speech. As a general rule, word initial or medial is pronounced or , but strictly as at the end of a word or before (as in ). Word initial or medial is pronounced or , and strictly as an at the end of the word or before (as in ), though this complementary distribution in allophones is not found among all speakers of Hejazi and some use and in all positions. 
Phonetic notes:
The close vowels can be distinguished by tenseness with long and being more tense in articulation than their short counterparts and in medial position, except at the end of words where they are all tense, e.g. short ('in') and long ('in him', 'there is').
Phonological processes.
The linking conjunction ('and') pronounced [u] is often linked with the consonant (before it) or the vowel (before or after it) or for emphasis only left as-is :-
Vowel Shortening.
Medial vowel shortening occurs before indirect object pronouns (e.g., ), where a medial word long vowel (⟨ي⟩ ,⟨ا⟩ and ⟨و⟩) in verbs is shortened. For example, عاد /ʕaːd/ "he repeated" becomes عاد لهم /ʕadlahum/ "he repeated to them" and رايحين له "going to him" is pronounced /raːjħinlu/ with a shortened /i/ and rarely /raːjħiːnlu/. This can also affect the spelling of the words depending on the writer, e.g. نروح becomes نرح لهم without the long vowel or it can be written نروح لهم but this does not effect third person masculine past verbs as in the example below.
Vowel shortening also occurs only in few words as in جاي "I'm coming" pronounced /d͡ʒaj/ or /d͡ʒaːj/.
Vowel lengthening.
Most word-final long vowels from the Classical period have been shortened in Hejazi but they are lengthened when suffixed, as in "they call" → "they call her".