To begin, it is necessary to explain the meanings of the terms mak͟hraj and ṣifāt. The mak͟hraj of a letter refers to the place from which its sound emerges, while the ṣifāt are the additional defining characteristics of the letter. To properly pronounce the Arabic letters for recitation of the Qurʾān, it is important to know the mak͟hārij and ṣifāt of these letters. Proper application of the mak͟hārij and ṣifāt of letters is what allows for the distinction and definition of each letter, producing eloquent and clear speech.

Makkī ibn ʾAbī Ṭālib mentions in his book ar-Riʿāyah[1] that all letters of Arabic have distinct sounds, as is necessary to produce reasonable and understandable speech, unlike the speech of animals which does not differ in mak͟hārij and ṣifāt. Letters that share a mak͟hraj differ in ṣifāt, and those that share in ṣifāt differ in mak͟hraj, and those that differ in both are even more distant. As-Sak͟hāwi also mentions something similar to what Makkī noted, in his explanation of as͟h-S͟hāṭibiyyah.[2]

Scholars mention that the best way to know the mak͟hraj and ṣifāt of a letter is to place a hamzat waṣl with kasr before it and put sukūn on it (e.g. اضْ), since the mak͟hraj of a letter is difficult accurately determine when it has a ħarakah on it. The mak͟hraj of the letter will be the place at which its sound ends. Now as for the letter ض, its description according to the scholars of tajwīd and the language, from past and present, is as follows:

Its mak͟hraj is the side of the tongue together with the neighboring side teeth. It is most easily and commonly pronounced from the left side of the mouth, and is less common and more difficult from the right side, and most rare and difficult from both sides, which is narrated to be the pronunciation of the Prophet صلى الله عليه وسلم and ʿUmar رضي الله عنه. The mak͟hraj of the ض extends from the beginning of the side of the tongue (parallel to the mak͟hraj of consonantal ي, which is at the middle of the tongue) together with the back molars up until the edge of the side of the tongue at the mak͟hraj of ل, which is pronounced from above the canine. The specific mak͟hraj of ض is not shared with any other letter, although ل also uses (the front of) the side of the tongue. Al-K͟halīl classified the letter ض into the same general mak͟hraj as ش ي ج, which is the middle of the tongue with the palate, but this does not contradict the view of the majority of scholars in terms of the pronunciation of the letter, and must be reconciled with it.

The ṣifāt of the ض are as follows:

1. Jahr – This refers to the strength of sound and prevention of breath flow due to strength of the reliance on the mak͟hraj, and its opposite is hams, which refers to the weakness of sound and the flow of breath with a letter due to the weakness of reliance on the mak͟hraj. The letters of hams are فحثه شخص سكت, while the rest of letters have jahr. It is important to note that the air flow here does not necessarily refer to the sound of a letter itself (which is why ت ك have hams and not jahr), and is exclusive to unvoiced air (i.e. air that is not vibrated with the vocal cords) and does not include voiced sound (which is why letters such as ز ذ غ have jahr). Jahr is considered a strong ṣifah, while hams is considered weak.
2. Rak͟hāwah – This refers to the flow of the sound of a letter at its mak͟hraj, and its opposite is s͟hiddah, which refers to the trapping of a letter’s sound at its mak͟hraj due to the strength of its adherence to its mak͟hraj. It should be noted that the sound here refers to the sound of the letter itself, regardless of whether that sound is voiced or not (which is why letters such as س ث خ have rak͟hāwah), and does not include extra air or sound coming out after a letter is pronounced (as in ت ك and with qalqalah). Rak͟hāwah is considered a weak ṣifah, while s͟hiddah is considered strong. There is also a middle category in between rak͟hāwah and s͟hiddah, known as tawassuṭ or bayniyyah. This category refers to the letters for which sound is prevented from flowing at the mak͟hraj, but is caused to flow outside of it. The letters of s͟hiddah are أجد قط بكت, and the letters of tawassuṭ are لن عمر (according to the majority), while the letters of rak͟hāwah are the remaining letters.
3. Istiʿlāʾ – This refers to the raising of the tongue up towards the palate when pronouncing the letter, and its opposite is istifāl, which is the tongue remaining low and separate from the palate. The letters of istiʿlāʾ are خص ضغط قظ, and the letters of istifāl are the rest. Certain other letters (ا ل ر) can have istiʿlāʾ in some cases and not others, which in such situations is more commonly known as tafk͟hīm, in contrast to tarqīq. Istiʿlāʾ is considered a strong ṣifah, while istifāl is considered weak.
4. ʾIṭbāq – This refers to the sticking and covering of (part of) the tongue to the palate such that the sound becomes restricted between the tongue and the palate, and its opposite is infitāħ, which refers to the space between the tongue and palate being left open. The letters of ʾiṭbāq are ص ض ط ظ, while the rest are letters of infitāħ. ʾIṭbāq is considered a strong ṣifah, while infitāħ is considered weak.
5. Istiṭālah – This refers to the long extension of the mak͟hraj from which sound emerges up into the location of ل, and it is exclusive to ض, and has no opposite. A minority of scholars mentioned tafas͟hs͟hī as a ṣifah for ض, which is normally known as an exclusive ṣifah of ش referring to the spreading out of the air throughout the mouth. Later scholars verified that what they meant for ض was the spreading of the mak͟hraj of ض, and not the air or sound,[3] which explains why such scholars tended not to mention istiṭālah as a ṣifah. Istiṭālah is considered a strong ṣifah.
6. ʾIṣmāt – This ṣifah refers to the fact that the letters that have it cannot be placed together in a root that contains over 3 letters without also including a letter of the opposite ṣifah, which is called ʾid͟hlāq and refers to the fact that those letters come from the edges of the tongue or lip. The letters of ʾid͟hlāq are فر من لب, and the letters of ʾiṣmāt are the rest. ʾIṣmāt and ʾid͟hlāq are both considered intermediate and have no value in terms of strength or weakness, and they also have no effect on determining the pronunciation of letters.

First, in comparison with the Ṭāʾī ض, some clear discrepancies can be noted. The correct pronunciation of ض comes from the side of the tongue together with the molars, while the Ṭāʾī ض is pronounced using the front of the tongue together with the roots of the upper central incisors (top middle 2 teeth), which is the mak͟hraj of ت د ط, and consequently the Ṭāʾī ض also cannot have istiṭālah. Furthermore, the correct pronunciation of ض has rak͟hāwah, while the Ṭāʾī ض is impossible to pronounce with rak͟hāwah and can only have s͟hiddah.

Now as for the Ẓāʾī ض, the discrepancy is less clear, and its proponents acknowledge and accept all these facts about its mak͟hraj and ṣifāt; the real question in their case is whether they are applying these properly. Through close contemplation and observation from attempting to pronounce the Ẓāʾī ض, one will notice that it is impossible to pronounce ض in such a way that it becomes nearly audibly indistinguishable from ظ, as the people of the Ẓāʾī ض do, without combining the mak͟hraj of ض with at least part of the mak͟hraj of ظ and making sound flow from outside of the proper mak͟hraj of the ض. As has already been mentioned, the mak͟hraj of ض does not extend any further than the location of the mak͟hraj of ل, and does not involve the incisors at all, which are the mak͟hraj of ث ذ ظ.

Furthermore, as can be noticed from the ṣifāt of ض, it is a very strong letter; it is in fact the 2nd strongest letter in the Arabic language, after ط, while ظ is the 4th coming after ق. The increased strength of ض includes that it is more intense than ظ in the ṣifāt of jahr, istiʿlāʾ, and ʾiṭbāq, and less intense in the ṣifah of rak͟hāwah, as has been discussed by past scholars. For that matter, it is impossible to precisely pronounce ض from the proper mak͟hraj without it having these differences, and consequently, equalizing ض with ظ in the intensity of these ṣifāt cannot be done without incorrectly infusing it with part of the mak͟hraj of ظ or causing sound to flow from outside the mak͟hraj. This imprecision in mak͟hraj becomes more clear when noting the fact that it is physically impossible to pronounce the Ẓāʾī ض from both sides of the mouth at once, as it necessarily requires blocking the location(s) from which most of its sound emerges, which goes against the fact mentioned by many scholars that it should be possible and is indeed valid to pronounce it from both sides at once.

The proponents of the Ẓāʾī ض argued against those who apply the proper ض with the same points that are used against the Ṭāʾī ض, claiming that nearly the entirety of the most learned reciters and most educated scholars of the Qurʾān and tajwīd across the world, upon whom the transmission of the Qurʾān is dependent, pronounce ض from the mak͟hraj of ت د ط rather than its proper mak͟hraj, and without rak͟hāwah or istiṭālah. This is utterly false, and anyone who has studied the Qurʾān and tajwīd from properly educated scholars, read books authored by such scholars, or watched videos by them on this topic, will know that they all command the same proper pronunciation of ض from its mak͟hraj and with its proper ṣifāt.

Pronunciation of ض as the Ṭāʾī ض is generally not practiced by properly educated reciters of Qurʾān, although it may be common among laymen and non-expert reciters. Some proponents of the Ẓāʾī ض may relinquish the laughably false claim that the well known ض among leading scholars of the Qurʾān is pronounced from the mak͟hraj of ت د ط and not its proper mak͟hraj, and resort instead to more mild and less obviously false claims, such as claiming that the ض known to the scholars incorrectly involves the tip of the tongue and front teeth in its mak͟hraj, or that it is too close in sound to د and not close enough to ظ. 

It is true that the pronunciation of ض involves the middle of the tongue and even the front in some sense, and not only its side, although it does not involve the front teeth at all, but this is simply the application of its ʾiṭbāq, and its mak͟hraj remains the side of the tongue with the side teeth. Past scholars such as Sībawayhi and others have explicitly mentioned that the letters of ʾiṭbāq involve 2 different parts of the tongue, one region being for the mak͟hraj while the rest of the tongue adheres to the palate, and that ʾiṭbāq entails constriction of the sound of the letter as such.[4] Scholars like ar-Raḍī al-Astarābād͟hī also mention that while the side of the tongue adheres to the side teeth when pronouncing ض, the rest of the tongue adheres to the palate.[5]

It has also already been noted that al-K͟halīl classified the mak͟hraj of ض as the middle of the tongue further forward than the mak͟hraj of ج, and we will later see that Ibn Sīnā states something similar in more explicit terms. Although that classification is incorrect, since the sound of the ض ends at the side of the tongue with the side teeth, the fact that this view was held by some is indicative of the fact that the middle of the tongue has an important role in the pronunciation of the letter. Whereas for letters like ظ and ص their ʾiṭbāq involves the sides of the tongue, for ض it instead involves the middle of the tongue, since the side of the tongue is being used as its mak͟hraj, and for ط the ʾiṭbāq is as complete as possible over the entirety of the palate (while the back of the tongue is already raised up to the palate for all letters of istiʿlāʾ).

Consequently, if the middle of the tongue is adhering to the palate and the side of the tongue is connecting with the side teeth, the front of the tongue must be placed in the area in front of these, as is even noted explicitly by past scholars, unless a person wishes to cut off the front of their tongue! For that matter, this aspect may not even differ with the Ẓāʾī ض. This must be done in such a way that the mak͟hraj of the ض is not changed, so the front of the tongue must be left in the area behind the teeth with a small space between the tongue and the teeth, without applying pressure that would produce a new mak͟hraj there. 

As for the sound of the proper ض, then it should not and indeed does not have any strong resemblance to د, and is much closer to ظ. The properly pronounced sound of ض can occasionally be confused for a ظ, especially when the listener does not recognize the word or verse being heard, while it would never be confused for a د. All that can be said here is that the sound of the well known ض resembles the Ṭāʾī ض, which is a د with the addition of istiʿlāʾ/tafk͟hīm and ʾiṭbāq and without qalqalah. Although this is true, it is not problematic, as even the ظ itself is relatively close to such a sound, while the properly pronounced well known ض should be and indeed is somewhat in between the sounds of the Ṭāʾī ض and the pure ظ. The Ṭāʾī ض is slightly closer in mak͟hraj, while the pure ظ is closer to the proper ض in ṣifāt due to its rak͟hāwah, although the proper ض falls between the two in strength and in the intensities of its ṣifāt. It also would not be expected for past scholars to have mentioned the proper ض as being close to any letter other than ظ (besides ل with tafk͟hīm), considering the Ṭāʾī ض is not a letter that exists in proper Arabic. 

Although the rak͟hāwah of ض as pronounced by scholars of the Qurʾān is not as clear as that of other letters of rak͟hāwah, due to what has already been mentioned regarding it being the strongest of the letters of this ṣifah, it is still undoubtedly being pronounced with rak͟hāwah. The rak͟hāwah of ض must naturally be noticeably less than that of other letters such as ظ, due to the fact that the mak͟hraj and ṣifāt of the ض leave a more constricted space for air to flow through. For ض, air can only flow through the space left between the teeth and tongue and the cheek in the side of the mouth, and more intense ʾiṭbāq constrict the space, while with ظ the air is free to flow straight through the middle of the mouth with minimal ʾiṭbāq constricting it. Consequently, the rak͟hāwah of ض cannot be equalized with that of ظ without decreasing its ʾiṭbāq and infusing it with part of the mak͟hraj of ظ and/or causing sound to flow from outside the mak͟hraj.

The more intense ʾiṭbāq of the ض is necessary to block sound from flowing in areas outside the mak͟hraj, and because of this, the sound that flows can only go through the side of the mouth where it may even end up filling the cheek. If this happens, then a person may not be able to continue to produce sound flow without causing it to occur from outside the mak͟hraj of ض, which produces a stronger and more noticeable rak͟hāwah like that of ظ, and requires weakened ʾiṭbāq. The fact that the Ẓāʾī ض involves part of the mak͟hraj of ظ can also be noticed by placing a finger in front of the front teeth and feeling the air coming from them, or by blocking that area with the tongue so sound cannot come from there, which ends up ceasing the sound of the Ẓāʾī ض. 

An attentive listener can easily notice the rak͟hāwah of ض, mainly in cases where it has sukūn, in the recordings of famous Qurʾān reciters, especially by comparing it to similar cases with ط or other letters of s͟hiddah. In general, scholars mention that the only case in which rak͟hāwah and s͟hiddah can clearly be differentiated is in the case of sukūn on a letter, as rak͟hāwah is not clearly noticeable when a letter has ħarakah. It is even easy to find explicit demonstrations of the rak͟hāwah of ض with its proper known pronunciation on Youtube. A few examples will be provided here. 

In this video, S͟hayk͟h ʾAyman Suwayd demonstrates and speaks in depth about the rak͟hāwah of ض. 

In this video, a student discusses the claim of the Ẓāʾī ض with the eminent scholar ʿAbd al-Bāsiṭ Hās͟him, and in the video ʿAbd al-Bāsiṭ Hās͟him demonstrates the rak͟hāwah of the proper ض. 

In this video, at timestamp 8:34 (514s), the prominent Egyptian scholar residing in al-Madīnah, ʿAbd ar-Rāfiʿ Riḍwān, demonstrates the rak͟hāwah of the proper ض in a discussion about the claim of the Ẓāʾī ض. 

From listening to these recordings, it is abundantly clear that what is being heard is neither pre-voicing nor a nasal sound, although the supporters of the Ẓāʾī ض may try to claim that this is what people think rak͟hāwah to be in the known ض. Nasalization would produce a completely distinct sound to what is heard in these videos, and it would be impossible to keep the sound flowing to the extent being done here just with pre-voicing. The proponents of the Ẓāʾī ض also ask an important question with regards to this; if the rak͟hāwah of ض is less than that of the other letters of rak͟hāwah, then why is it placed in the category of rak͟hāwah and not the category of tawassuṭ/bayniyyah? To properly answer this question, it is first necessary to analyze the letters of tawassuṭ, and determine the reasons for their placement in a middle category separate from the letters of s͟hiddah and rak͟hāwah. 

Ar-Raḍī al-Astarābād͟hī, in his explanation on Ibn al-Ħājib’s S͟hāfiyah, after quoting Sībawayhi’s classifications on the mak͟hārij and ṣifāt, explains the reasoning for the category of tawassuṭ.[6] He says that for the letters of tawassuṭ, their sound is indeed trapped at the locations of their mak͟hārij, but unlike the letters of s͟hiddah, these letters have factors that cause sound to flow from other locations. It is for this reason that many early scholars, such as Sībawayhi, ad-Dānī,[7] al-Qurṭubī,[8] and others referred to these letters as the letters of s͟hiddah for which sound still flows. It it useful to note that, as already mentioned before, ar-Raḍī says the rak͟hāwah/s͟hiddah of letters can only be tested when there is sukūn on them. As-Sīrāfī also mentions similar things to ar-Raḍī in his explanation on al-Kitāb by Sībawayhi, adding some more details for the claim that the sound of the letters of madd and līn do not flow from their mak͟hārij.[9] 

First, for the ع, ar-Raḍī says that its sound is trapped at its mak͟hraj, but due to its closeness with the ح which has hams, a small amount of sound slips out, as if one were stopping on ح. Indeed, from consideration on the pronunciation of the letter ع, the tawassuṭ of ع can be most clearly noticed when comparing it to ح and ء in positions of sukūn or tas͟hdīd. As for ل, then due to its inħirāf, the sound flows with it because the placement of the tongue for its mak͟hraj only blocks the flow of sound at the mak͟hraj itself, thereby allowing sound to flow through the rest of the mouth. For م and ن, the sound flows from the nose as g͟hunnah, as demonstrated by the fact that plugging the nose stops the sound from flowing. Finally, for ر, its sound does not flow initially when it is pronounced, but a small amount is allowed to flow due to its inħirāf towards ل, and its takrīr also means that rolling it to produce many ر sounds makes the sound flow. According to the views of many scholars, including Sībawayhi, the letters of madd and līn (the letters of madd are the long vowels و ا ي and the letters of līn are و ي with sukūn when preceded by a fatħah) are included among the letters of tawassuṭ, and this is due to the fact that these scholars classified their mak͟hārij differently. The scholars who held this view did not include the Jawf (the opening in the chest) as a mak͟hraj, and instead classified و and ي with their consonantal forms and ا with ء in mak͟hraj. Since the sound for these letters comes from the Jawf and not the places that these scholars considered their mak͟hārij to be, it follows that they would be considered among the letters of tawassuṭ, despite their sound flow being more than that of any other letters, as their sound under this view does not flow from their mak͟hārij. 

As can be observed from this explanation, a letter’s classification into the category of tawassuṭ has little to do with the amount of sound that flows with it. Indeed, it is often the case that letters of tawassuṭ can have a greater flow of sound than letters of rak͟hāwah, and this is especially true according to the view that the letters of madd are in the category of tawassuṭ, since their sound flow is greater than any of the letters of rak͟hāwah. Rather, the category of tawassuṭ, as mentioned, is for letters for which the sound does not properly flow from their mak͟hārij, and instead flows from other places. When this classification is understood, it becomes clear that the proper ض cannot be placed in the category of tawassuṭ. Although it has less rak͟hāwah than the rest of the letters having this ṣifah, its rak͟hāwah still falls within their general category, and has no relation to the purpose of the category of tawassuṭ.

It may also be worth noting that many modern academics incorrectly claim that ع should be a letter of rak͟hāwah, due to the fact that its sound may seem to flow at its mak͟hraj. In reality, as mentioned, when it is properly pronounced the sound that continues does not remain the same, and instead is a slipping of a small amount of sound that resembles a ح. When one notes the verified view of scholars that every single letter has its own specific mak͟hraj, and that the mak͟hārij mentioned by scholars are generalizations and approximations, this matter becomes more clear.[10] If pronounced improperly, one may produce a flowing sound with ع that resembles a constricted vowel. 

The incorrect assumption of the Ẓāʾī ض proponents that the pronunciations of letters can simply be reconstructed from descriptions of past scholars leads them to an error with many severely problematic consequences. This is the same path that orientalists have followed, which led them to claiming new unheard of reconstructed pronunciations for letters of the Arabic language in contradiction to the consensus of the scholars of the Qurʾān. Many of the proponents of the Ẓāʾī ض may even appeal to orientalists and modern academics on the pronunciation of the letter, despite the fact that the vast majority of orientalist academics do not even hold to original pronunciations of ض that are nearly identical in sound to that of ظ (the supposed original sound [ɮˤ] according to the main preponderant view among orientalist academics can be heard here, and it is very easily distinguishable from the sound of ظ, and from the sound of the Ẓāʾī ض which can be heard here and here). For that matter, the main orientalist view on the pronunciation of ض is comparably far in sound, if not further, than the well known ض is from the Ẓāʾī ض! Even more ironically, there are actually major views among orientalists that hold to [d͡ɮˤ] or [dˡˤ] as the original pronunciation of ض, which are much closer in sound to the pronunciation of ض that is well known among scholars of the Qurʾān than they are to the Ẓāʾī ض. 

The Ẓāʾī ض proponents also argued that since ظ is the closest letter to ض, sharing in all of its ṣifāt except for istiṭālah while also differing in mak͟hraj, then the correct pronunciation of ض should closely resemble that of ظ. While it is true that ظ should be and is indeed the closest of the Arabic letters in sound to ض due to their closeness in ṣifāt, it is not the case that this closeness entails their sounds should resemble each other to such an extent that they become practically indistinguishable by ear. Rather, all of the letters of the Arabic language must have distinct and discernible sounds from each other when properly pronounced, and this has been mentioned explicitly by past scholars, as noted at the beginning of the section. The invalidity of this reasoning can be most easily shown by analogy with other cases. 

The ل and ر, for example, share in all of their ṣifāt except for the takrīr that is in the ر, and differ slightly in mak͟hraj. The mak͟hraj of ل is very close to that of ر, with a minority of scholars having even considered them to be a single mak͟hraj, and one of the ṣifāt shared by ل and ر, their inħirāf, even alludes to the fact that they tend towards each other in mak͟hraj. Despite this close similarity, which is surely greater than the similarity between ظ and ض, the letters ل and ر are very easily audibly distinguishable when correctly pronounced. Another example is that of ت and ك, which are identical in ṣifāt and differ only in mak͟hraj, being comparably distant to ظ and ض in mak͟hraj. Despite this, there is also very little confusion that occurs between their sounds. Yet another example is that of س and ز, which are identical in mak͟hraj and share in ṣifāt except for the hams of س and jahr of ز. Despite the fact that all of these letters should be closer to each other than, or at minimum comparably close to ظ and ض, we find that they are all clearly distinguishable by ear without issues. Consequently, it is only reasonable that ظ and ض should also be clearly distinguishable by ear. 

Finally, one of the most flimsy justifications of some of the proponents of the Ẓāʾī ض is that Arabic loans in other languages pronounce ض as a z sound, and this sound is only similar to the Ẓāʾī ض and not the well known ض. This is an argument based on ignorance, as the only group that directly took ض from Arabic and (seemingly) turned it into a z sound were the Persians. As for the Turks and Indians, then they received Arabic words through Persian, leading to them imitating the pronunciations used by the Persians that were near them from whom they heard the words. When we look at other languages that took loanwords directly from Arabic without intermediaries, we find that they did not normally change the sound of ض into a z.[11] Such languages include Malay, Swahili, Hausa, and Romance languages, and this even includes the names of pagan Arab idols found in Akkadian, which all normally (or exclusively for Akkadian) turned ض into sounds such as d or l (or d͟h in the case of Swahili) or combinations of both, whereas for ظ, these languages (other than Swahili which also changed it to d͟h) normally turned it into a z sound. 

It is also useful to note that it is highly likely most Persians initially pronounced ض as ذ before the pronunciation eventually changed to a z sound, since in the early Islamic period most Persian/Iranic dialects (mainly the ones that were not far in the east) had the ذ sound natively,[12] as did even a large portion of Turks. It is also useful to note the fact that in Arabic dialects that produced the Ṭāʾī ض, they more commonly changed ظ into a voiced ص sound than they did with ض, leading to the inaccurate differentiation between ض and ظ that comes from these dialects. Considering all of these facts, a holistic and thorough historical linguistic observation would lead one to conclude that the original classical pronunciation of ض was likely closer in sound to d than to z. 

Regardless, none of these things can be taken as strong proof for what the correct pronunciation of ض should be, as languages often make drastic changes to the pronunciations of loanwords and in the evolution of their own sounds, and the resulting sounds are not necessarily especially close to the original ones, although they may be close relative to the other sounds present in that language. This is indeed the case, as z is among the closest sounds to ض that exists in Persian, despite not being especially close to it overall, especially when considering other sounds present in Arabic. It is also a possibility that Persians may have heard the pronunciation of Arabs who pronounced ض as ظ, which was not uncommon in the regular speech of lay-Arabs. 

CITATIONS: 

[1] –  الرعاية لمكي – ص156 

[2] –  فتح الوصيد في شرح القصيد للسخاوي – ج2 ص533 

[3] –  شرح الجعبري على الشاطبية 

[4] –  شرح الجاربردي على الشافية – ص 365 , الكتاب لسيبويه – ج4 ص436 

[5] –  شرح الشافية للرضي – ج3 ص262 

[6] –  شرح الرضي الاستراباذي على شافية ابن الحاجب – ج3 ص260 

[7] –  التحديد لأبي عمرو الداني – ص108 

[8] –  الموضح في التجويد لعبد الوهاب القرطبي – ص89 

[9] –  شرح كتاب سيبويه للسيرافي – ج5 ص395 

[10] –  هداية القاري للمرصفي – الفصل الأول 

[11] –  Compilation and Creation in Adab and Luġa – LOANWORDS FROM ARABIC AND THE MERGER OF ḍ/ḏ 

[12] –  PERSIAN LANGUAGE i. Early New Persian – Phonology , ذال معجم – ویکی‌پدیا، دانشنامهٔ آزاد