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Manners of articulation
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Clicks are speech sounds found as consonants in many languages of southern Africa, and in three languages of East Africa. Examples of these sounds familiar to English speakers are the tsk! tsk! (American English) or tut-tut (British English) used to express disapproval or pity, the tchick! used to spur on a horse, and the clip-clop! sound children make to imitate a horse trotting.

Technically, clicks are obstruents articulated with two closures (points of contact) in the mouth, one forward and one at the back. The pocket of air enclosed between is rarefied by a sucking action of the tongue (i.e. clicks have a velaric/lingual ingressive airstream mechanism). The forward closure is then released, producing what may be the loudest consonants in the language, although in some languages such as Hadza and Sandawe, clicks can be more subtle and may even be mistaken for ejective stops.


What clicks sound like

For several sound samples see articles bilabial clicks, dental clicks, alveolar clicks, lateral clicks, and palatal clicks.

There are five places of articulation at which click consonants occur. In IPA, a click is symbolized by placing the assigned symbol for the place of click articulation adjacent to a symbol for a nonclick sound at the rear place of articulation. The IPA symbols are used in writing most Khoisan languages, but Bantu languages such as Zulu typically use Latin c, x and q for dental, lateral, and alveolar clicks respectively.

  • The easiest clicks for English speakers are the dental clicks written with a single pipe, ǀ. They are all sharp (high-pitched) squeaky sounds made by sucking on the front teeth. A simple dental click is used in English to express pity or to shame someone, and sometimes to call an animal, and is written tsk! in American English, or tut-tut! in British English.
  • Next most familiar to English speakers are the lateral clicks written with a double pipe, ǁ. They are also squeaky sounds, though less sharp than ǀ, made by sucking on the molars on either side (or both sides) of the mouth. A simple lateral click is made in English to get a horse moving, and is conventionally written tchick!
  • Then there are the bilabial clicks, written with a bull's eye, ʘ. These are lip-smacking sounds, but without the pursing of the lips found in a kiss.

The above clicks sound like affricates, in that they involve a lot of friction. The other two families are more abrupt sounds that do not have this friction.

  • With the alveolar clicks, written with an exclamation mark, ǃ, the tip of the tongue is pulled down abruptly and forcefully from the roof of the mouth, sometimes using a lot of jaw motion, and making a hollow pop! like a cork being pulled from an empty bottle. These sounds can be quite loud.
  • Finally, the palatal clicks, ǂ, are made with a flat tongue, and are softer popping sounds than the ǃ clicks.

Languages with clicks

Clicks occur in all three Khoisan language families of southern Africa, where they may be the most numerous consonants. To a lesser extent they are found in two groups of neighbouring Bantu languages which borrowed them, directly or indirectly, from Khoisan. In the southeast, in eastern South Africa, Swaziland, Lesotho, Zimbabwe, and southern Mozambique, they were adopted from a Tuu language or languages by the languages of the Nguni cluster (especially Zulu, Xhosa, and Phuthi, but also to a lesser extent Swazi and Ndebele), and spread from them in a reduced fashion to the Zulu-based pidgin Fanagalo, Sesotho, Tsonga, and Ronga, and more recently to Ndau and urban varieties of Pedi, where the spread of clicks is an ongoing process. The second point of transfer was near the Caprivi Strip and the Okavango River, where it was apparently the Yeyi language which borrowed the clicks from a West Kalihari Khoe language, and which in turn passed on a reduced click inventory to the neighboring Mbukushu, Kwangali, Gciriku, Kuhane, and Fwe languages in Angola, Namibia, Botswana, and Zambia.[1]

There are three minority languages in East Africa which use clicks: Sandawe and Hadza of Tanzania, as well as Dahalo, an endangered South Cushitic language of Kenya which has clicks in only a few dozen words. It is thought these may remain from an episode of language shift.

The only non-African language known to employ clicks as regular speech sounds is Damin, a ritual code used by speakers of Lardil in Australia. One of the clicks in Damin is actually an egressive click, using the tongue to compress the air in the mouth for an outward (egressive) "spurt".

The Southern African Khoisan languages only utilize root-initial clicks. Hadza, Sandawe, and several of the Bantu languages also allow syllable-initial clicks within roots, but in no known language does a click close a syllable or end a word.

English and many other languages may use clicks in interjections, such as the dental "tsk-tsk" sound used to express disapproval, or the lateral tchick used with horses. In Ningdu Chinese, flapped nasal clicks are used in nursery rhymes, and in Persian, Greek, Maltese and in southern Italian dialects such as Sicilian a click accompanied by tipping the head upwards signifies "no". Clicks occasionally turn up elsewhere, as in the special registers twins sometimes develop with each other, and in onomatopoeic usages.

The fictional native language of the Tenctonese in the film and television series Alien Nation incorporates some soft click consonants.

The airstream

The essence of a click is an ingressive airstream mechanism. However, in nasal clicks the nasalization involves a separate nasal airstream, generally pulmonic egressive but occasionally pulmonic ingressive. Similarly, voiced clicks also require a simultaneous pulmonic egressive airstream to power the voiced phonation.

The front articulation may be coronal or, more rarely, labial. The rear articulation has traditionally been thought to be velar or, again more rarely, uvular. However, recent investigation of Nǀuu has revealed that the supposed velar–uvular distinction is actually one of a simple click versus a click–plosive airstream contour, and that all rear articulations in Nǀuu are uvular or even pharyngeal. Even in languages without such a distinction, such as Xhosa, experiments have shown that when the click release is removed from a recording, the resulting sound is judged to be uvular, not velar. However, it is possible other languages do have a velar articulation.

Since in at least some languages clicks are not velar, some phoneticians have recently come to prefer the term lingual (made with the tongue) as being more accurate for this airstream mechanism than velaric (made with the velum).

Types of clicks

As noted above, clicks necessarily involve at least two closures: an anterior articulation which has traditionally been represented by the special click symbol in the IPA, and a posterior articulation which has been traditionally described as oral or nasal, voiced or voiceless, etc. The literature also describes a contrast between velar and uvular rear articulations for some languages. However, recent work has shown that for languages which make this distinction, all clicks have a uvular, or even pharyngeal, rear closure, and that the clicks explicitly described as uvular are in fact clusters/contours of a click plus a pulmonic consonant, in which the clusters/contour has two release bursts, the click itself and then a uvular consonant. In the case of "velar" clicks in these languages, on the other hand, there is only a single release burst, that of the forward click release, and the release of the rear articulation isn't audible.[citation needed]

Nonetheless, in most of the literature the stated place of the click is the anterior articulation (called the release or influx), while the manner is ascribed to the posterior articulation (called the accompaniment or efflux), as in a "nasal dental click".

There are numerous manners of clicks. These include what has been described as voiceless, voiced, aspirate, breathy voiced, nasal, voiceless nasal, breathy voiced nasal, glottalized, voiceless nasal glottalized, affricate, ejective affricate, prevoiced, prenasalized. In a few of the Khoisan languages, clicks cluster with other obstruents. Examples of such clusters in ǃXóõ a voiced velar click followed by voiceless affricated ejective, [ɡǃkxʼ], and a velar ejective click followed by uvular ejective, [kǃʼqʼ][2].

The size of click inventories ranges from as few as three (in Sesotho) or four (in Dahalo), to dozens in the Juu and Tuu languages (Northern and Southern Khoisan). ǃXóõ, a Tuu language, has fifty click phonemes[2] and over 70% of words in the dictionary of this language begin with a click.[3]

Clicks appear more stop-like or more affricate-like depending on their place of articulation: In southern Africa, clicks involving an apical alveolar or laminal postalveolar closure are acoustically abrupt and sharp, like stops, while bilabial, dental, and lateral clicks typically have longer and acoustically noisier releases that are more like affricates. In East Africa, however, the alveolar clicks tend to be flapped, while the lateral clicks tend to be more sharp and abrupt.


The five click releases with dedicated symbols in the International Phonetic Alphabet (IPA) are bilabial ʘ, dental ǀ, palato-alveolar or "palatal" ǂ, (post)alveolar or "retroflex" ǃ, and alveolar lateral ǁ. In most languages, the retroflex and palatal releases are "abrupt"; that is, they are sharp popping sounds with little frication (turbulent airflow). The bilabial, dental, and lateral releases, on the other hand, are typically "noisy": they are longer, lip- or tooth-sucking sounds with turbulent airflow, and are sometimes called affricates. (This applies to the forward articulation; both may also have either an affricate or non-affricate rear articulation as well.) The apical releases, ǃ and ǁ, are sometimes called "grave", because their pitch is dominated by low frequencies; while the laminal releases, ǀ and ǂ, are sometimes called "acute", because they are dominated by high frequencies. (At least in the Nǀu language, this is associated with a difference in the placement of the rear articulation: "grave" clicks are uvular, whereas "acute" clicks are pharyngeal.) Thus the alveolar click /ǃ/ sounds something like a cork pulled from a bottle (a low-pitch pop), at least in Xhosa; while the dental click /ǀ/ is like English tsk! tsk!, a high-pitched sucking on the incisors. The lateral clicks are pronounced by sucking on the molars of one or both sides. The bilabial click /ʘ/ is different from what many people associate with a kiss: the lips are pressed more-or-less flat together, as they are for a [p] or an [m], not rounded as they are for a [w].

The most populous languages with clicks, Zulu and Xhosa, use the letters c, q, x, by themselves and in digraphs, to write click consonants. Most Khoisan languages, on the other hand (with the notable exceptions of Naro and Sandawe), use a more iconic system based on the pipe <|>. (The exclamation point for the "retroflex" click was originally a pipe with a subscript dot, along the lines of ṭ, ḍ, ṇ used to transcribe the retroflex consonants of India.)

Competing orthographies
bilabial dental alveolar palatal lateral
Khoisanist ʘ ǀ ǃ ǂ ǁ
old IPA ʇ ʗ ° ʖ
Bantu c q * x

* The bilabial and palatal clicks do not occur in written Bantu languages. However, the palatal clicks have been romanized in Naron and Juǀʼhõasi, where they are transcribed with tc and ç respectively.

There are a few less well attested articulations, such as a noisy laminal denti-alveolar lateral release (<Ⅲ> [triple pipe] in an ad hoc transcription), which contrasts with an apical postalveolar lateral in Mangetti Dune ǃKung; an abrupt sub-apical retroflex release <‼> in Angolan ǃKung; and a "slapped" alveolar click <ǃ¡> in Hadza and Sandawe, where the tongue slaps the bottom of the mouth after the release. (These distinctions may suffice for the Damin releases as well.) However, the Khoisan languages are poorly attested, and it is quite possible that, as they become better described, more click releases will be found.

In the literature, the places not directly supported by the IPA are transcribed with ad hoc digraphs:

Provisional extended click symbols
bilabial dental alveolar retroflex palatal
Central ʘ ǀ ǃ ǂ
Lateral ǀǀǀ ǁ ǂǂ
Flapped ǃ¡

Typically when a click consonant is transcribed, two symbols are used, one for each articulation, connected with a tie bar. This is because a click such as [ŋ͡ǂ] has been traditionally been analysed as a nasal velar rear articulation [ŋ] pronounced simultaneously with the forward ingressive release [ǂ]. The symbols may be written in either order, depending on the analysis. However, a tie bar is not often used in practice, and when the manner is a simple [k], it will often be omitted as well. That is, <ǂ> = <kǂ> = <ǂk> = <k͡ǂ> = <ǂ͡k>.

The manner of a click is generally written before the release: <ŋ͡ǂ> or <ŋǂ>, and this is preferred by the IPA. However, many Khoisanists prefer to write the manner second: <ǂ͡ŋ> or <ǂŋ>. This is because any diacritics which follow belong to the manner rather than to the forward release, and they are more easily understood when they are made diacritics of the manner. Regardless, elements which do not overlap with the release are always written according to their temporal order: Prenasalization is always written first in <ŋɡ͡ǂ> = <ŋǂ͡ɡ>, and the second ejective is always written second in <k͡ǂʼqʼ> = <ǂ͡kʼqʼ>.

Some linguists analyze clicks as simplex segments, and use superscripts rather than digraphs for the accompaniments. Thus <ᶢǂ, ᵑǂ> or <ǂᶢ, ǂᵑ> = <ɡ͡ǂ, ŋ͡ǂ>

While the SAMPA encoding for IPA into ASCII doesn't have symbols for transcribing clicks, the proposed X-SAMPA standard does: O\, |\, |\|\, =\, and !. Some instead suggest ||\, #\ or "\ for the alveolar lateral click. The Kirshenbaum system uses a different method: clicks are denoted by digraphs, with the click symbol (always "!") added to the stop homorganic to the release, but with the manner of the accompaniment. For example, /t!/ is a voiceless dental click, and /m!/ is a nasal bilabial click. (This transcription is used in the literature on Damin.) However, the International Phonetic Association recommends using the IPA symbols in Unicode, or using the number codes which they have assigned to each symbol.

Places of articulation

These are often called click types, releases, or influxes. There are seven or eight known releases, not counting slapped or egressive clicks. These are bilabial affricated ʘ, or "bilabial"; laminal denti-alveolar affricated ǀ, or "dental"; apical (post)alveolar plosive ǃ, or "alveolar"; laminal postalveolar (palato-alveolar) plosive ǂ, or "palatal"; subapical postalveolar (retroflex) ǃ˞ (in central Ju); and two lateral clicks, which in the only dialects known to distinguish them (northern Ju) are laminal denti-alveolar lateral ǁ̻ with a forward release, and apical postalveolar lateral ǁ̺ with a rear release. There may be an additional palatal lateral click (a palatal click with a lateral release), provisionally transcribed ǂǂ, in another Ju lect which is currently (2008) being investigated. Given the poor state of documentation of Khoisan languages, it is quite possible that additional releases will turn up. However, no language is known to contrast more than five places of articulation.

Click release
dental ǀ only Dahalo
alveolar ǃ only Sesotho
3 releases, ǀ, ǃ, ǁ Sandawe, Hadza, Xhosa, Zulu (in Hadza and sometimes Sandawe, ǃ is "slapped";
Hadza also has a single word with ʘ)
4 releases, ǀ, ǂ, ǃ, ǁ Korana, Nama, Yeyi, Zhuǀ'hõasi (southeastern Ju)
4 releases, ǀ, ǂ, ǃ˞, ǁ ǃKung (Grootfontein)
5 releases, ʘ, ǀ, ǂ, ǃ, ǁ ǂHõã, Nǀu, ǀXam, ǃXóõ
5 releases, ǀ, ǂ, ǃ, ǁ̺, ǁ̪ ǃKung (Angola)
5 releases, ʘ, ʘ↑, ǀ, ǃ, ǃ˞ Damin

Extra-linguistically, Coatlán Zapotec of Mexico uses a linguolabial click, [ǀ̼ʔ], as mimesis for a pig drinking water.[4]


Names found in the literature

The terms for the click releases were originally developed by Bleek in 1911. Since then there has been some conflicting variation. Here are the terms used in some of the main references.

Click release Bantu letters Also known as:
ǀ dental c dental affricative/affricated/with friction; alveolar affricated; denti-alveolar; apico-lamino-dental; denti-pharyngeal
ǂ palatal palato-alveolar; alveolar; alveolar instantaneous; denti-alveolar implosive; palato-pharyngeal
ǃ alveolar q cerebral; (post-) alveolar implosive; palato-alveolar; palato-alveolar instantaneous; palatal; palatal retroflex; apico-palatal; central alveo-uvular
ǁ lateral x lateral affricative/with friction; alveolar lateral affricated; post-alveolar lateral; lateral apico-alveo-palatal; lateral alveo-uvular

The back-vowel constraint

The shape of the tongue in Nama when articulating an alveolar click (blue) and a palatal click (red) [throat to the right]. The articulation of the vowel [i] is slightly forward of the red line, with its peak coinciding with the dip of the blue line.

In several languages, including Nama and Ju|’hoansi, the alveolar and lateral clicks only occur, or preferentially occur, before back vowels, while the dental and palatal clicks may occur before any vowel. The effect is most noticeable with the high front vowel [i]. In Nama, for example, the diphthong [əi] is common but [i] is rare after alveolar clicks, whereas the opposite is true after dental and palatal clicks. This is a common effect of uvular or uvularized consonants on vowels in both click and non-click languages. In Taa, for example, the back-vowel constraint is triggered by both alveolar clicks and uvular stops, but not by palatal clicks or velar stops: sequences such as */ǃi/ and */qi/ are rare to non-existent, whereas sequences such as /ǂi/ and /ki/ are common.

Miller et al. (2003) used ultrasound imaging to show that the rear articulation of the alveolar clicks ([ǃ]) in Nama is substantially different that that of palatal and dental clicks. Specifically, the shape of the body of the tongue in palatal clicks is very similar to that of the vowel [i], and involves the same tongue muscles, so that sequences such as [ǂi] involved a simple and quick transition. The rear articulation of the alveolar clicks, however, is several centimeters further back, and involves a different set of muscles in the uvular region. The part of the tongue required to approach the palate for the vowel [i] is deeply retracted in [ǃ], as it lies at the bottom of the air pocket used to create the vacuum required for click airstream. This makes the transition required for [ǃi] much more complex and the timing more difficult than the shallower and more forward tongue position of the palatal clicks. Consequently, [ǃi] takes 50 ms longer to pronounce than [ǂi], the same amount of time required to pronounce [ǃəi].

Manners of articulation

(Data is primarily from Ladefoged; see references at individual language articles.)

Click manners are often called click accompaniments or effluxes, but both terms have met with objections on theoretical grounds.

There is a great variety of click manners, both simplex and complex, the latter variously analysed as consonant clusters or contours. With so few click languages, and so little study of them, it is also unclear to what extent clicks in different languages are equivalent. For example, the [ǃkˀ] of Nama, [ǃkˀ ~ ŋˀǃk] of Sandawe, and [ŋ̊ǃˀ ~ ŋǃkˀ] of Hadza may be essentially the same phone, as may [ǃk͡xʼ] and [ǃq͡χʼ]; no one language distinguishes either set, and the differences in transcription may have more to do with the approach of the linguist than with actual differences in the sounds. Such suspected allophones/allographs are linked through a common bullet in the left-hand column in the table below.

Some Khoisan languages are typologically unusual in allowing mixed voicing in non-click consonant clusters/contours, such as dt͡sʼk͡xʼ, so it is not surprising that they would allow mixed voicing in clicks as well.

There is ongoing discussion as to which clicks are best analysed as consonant clusters. For example, some linguists feel that ejective clicks are not possible, and indeed in many Khoisan languages they appear to be clusters. However, in other languages, phonetic measurements have found that, although the ejective release follows the click release, it is the rear closure of the click that is ejective, not a subsequent consonant. (In Ladefoged's analysis in the table below, if there is only a single segment, this is indicated by a single non-subscript letter for the accompaniment.) This is one reason for analysing such clicks as airstream contours instead of clusters.

Of the languages illustrated below,

(all spoken primarily in Namibia and Botswana; Nama is like Korana except it has lost [ǃk͡xʼ])

The four Dahalo manners occur only with a dental release. Damin has only nasal clicks, but in addition has an oral "spurt" that might be considered an egressive click.

IPA Manner ǃXóõ Nǀuu ǂHoan Juǀ’hõa Korana Gǀui Sandawe Hadza Dahalo Xhosa Yeyi Damin
[ǃk] Tenuis velar plosive •* •*
[ǃkʰ] Aspirated velar plosive •* •*
[ǃkˀ] Tenuis velar plosive and glottal stop •*
Voiceless glottalized velar plosive
(prenasalized between vowels)
[ŋ̊ǃˀ] Voiceless velar nasal and glottal stop •*
[ǃɡ] Voiced velar plosive •* •*
[ǃɡx, ǃɡ͡ɣ, ǃɡʱ] Voiced affricated velar plosive
[ǃɡʱ] Breathy-voiced velar plosive •*
[ǃɡˀ] Creaky velar plosive •*
[ǃŋ] Voiced velar nasal •* •*
[ǃŋʱ] Breathy-voiced velar nasal
[ǃŋ̊] Voiceless velar nasal •*
[ŋ̊ǃh] Voiceless delayed-aspirated velar nasal •*
[ŋ̊↓ǃh] Voiceless ingressive pulmonic nasal with delayed aspiration
[ʔǃŋ] Preglottalized velar nasal •*
[ŋǃŋ̊ʰ] Voiced velar nasal, plus voiceless aspirated velar nasal
[ǃq] Tenuis uvular plosive
[ǃqʰ] Aspirated uvular plosive
[ǃk͡x] Voiceless affricated velar plosive
[ǃq͡χ] Voiceless affricated uvular plosive
[ǃqʼ] Uvular ejective
[ǃk͡xʼ] Affricated velar ejective
[ǃq͡χʼ] Affricated uvular ejective
[ǃkʼqʼ, ǃkʼk͡xʼ] Voiceless velar ejective, plus uvular ejective
[ǃɡh, ǃɡkʰ] Voiced velar plosive followed by aspiration
[ǃɡk͡x] Voiced velar plosive, plus voiceless velar fricative
[ǃɡk͡xʼ] Voiced velar plosive, plus voiceless affricated ejective (perhaps /ǃɡʱ/)
[(ɴ)ǃɢ] Voiced uvular plosive (usually prenasalized)
[(ɴ)ǃɢh, (ɴ)ǃɢx, (ɴ)ǃɢʀ] Voiced (or prenasalized) uvular plosive, plus aspiration, velar fricative, or uvular trill

A DoBeS (2008) study found several additional manners for ǃXóõ. However, these were reanalized as consonant clusters, leaving this most complex inventory in the table above with only nine manners of clicks (these are asterisked in the table): tenuis /kǂ/, voiced /ɡǂ/, aspirated /kǂʰ/, breathy voiced /ɡǂʱ/ (which Traill had analyzed as a cluster /ɡǂqʰ/), ejective /kǂʼ/, creaky /ɡǂˀ/, nasal /ŋǂ/, a true voiceless nasal /ŋ̊ǂ/, and preglottalized nasal /ˀŋǂ/ (which Traill had analyzed as a cluster /ˀnkǂ/). Those believed to be clusters are [qǂ] = /kǂq/, [ɢǂ] = /ɡǂq/, [kǂʰ] = /kǂqʰ/, [ɡǂh] = /ɡǂqʰ ~ ɡǂɢʱ/, [qǂʼ] = /kǂqʼ/, /ɡǂqʼ/, [kǂˣ] = /kǂx/, [ɡǂx] = /ɡǂx/, [kǂʼqʼ] = /kǂqxʼ/, [ɡǂqʼ] = /ɡǂqxʼ/, [kǂˀ] = /kǂʔ/, /ɡǂʔ ~ ŋǂʔ/, [↓ŋ̊ǂʰ] = /kǂh ~ ŋ̊ǂh/, [ɢǂh] = /ɡǂh ~ ŋǂh/.

Similarly, Miller (2007) found six of the ten manners in Nǀu to be simple clicks, with the other four being airstream contours.

Click genesis and click loss

Clicks are often portrayed as a primitive or primordial feature of human language, but we have no reason to suspect that they are very old compared to other speech sounds. In fact, given their complexity, they may be relatively recent. How clicks arose is not currently known. Some linguists speculate that clicks were initially used for taboo avoidance and then borrowed into regular speech. (Compare Damin.) Others suggest that they developed from other complex consonants. For example, the Sandawe word for 'horn', [tɬana], with a lateral affricate, may be a cognate with the root [ŋǁaː] found throughout the Khoe family, which has a lateral click. This and other words suggests that at least some Khoe clicks may have formed from consonant clusters when the first vowel of a word was lost; in this instance [tɬana][tɬna][ǁŋa] (= [ŋǁa]).

On the other side of the equation, several non-endangered languages in vigorous use demonstrate click loss. For example, the East Kalahari languages have lost a large percentage of their clicks, presumably due to Bantu influence. As a rule, a click is replaced by a consonant with the manner of articulation of the accompaniment and the place of articulation of the forward release: alveolar click releases (the [ǃ] family) tend to mutate into a velar stop or affricate, such as [k], [ɡ], [ŋ], [k͡x]; palatal clicks ([ǂ] etc.) tend to mutate into a palatal stop such as [c], [ɟ], [ɲ], [cʼ], or a post-alveolar affricate [tʃ], [dʒ]; and dental clicks ([ǀ] etc.) tend to mutate into an alveolar affricate [ts].


  1. ^ Derek Nurse & Gérard Philippson (2003) The Bantu languages, pp 31–32
  2. ^ a b L&M 1996, p 266
  3. ^ L&M 1996, p 246
  4. ^ Rosemary Beam de Azcona, Sound Symbolism. Available at

See also


  • Ladefoged, Peter. 1968. A phonetic study of West African languages: An auditory-instrumental survey. Cambridge University Press, 2nd edition. ISBN 0-521-06963-7
  • Ladefoged, Peter; Ian Maddieson (1996). The Sounds of the World's Languages. Oxford: Blackwell. ISBN 0-631-19814-8. 
  • Amanda Miller, Levi Namaseb, Khalil Iskarous. 2003. Tongue Body constriction differences in click types.
  • Traill, Anthony & Rainer Vossen. 1997. Sound change in the Khoisan languages: new data on click loss and click replacement. J African Languages and Linguistics 18:21-56.

External links


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