Click consonant

Click consonants occur at six principal places of articulation. The International Phonetic Alphabet (IPA) provides five letters for these places (there is as yet no dedicated symbol for the sixth).

• The easiest clicks for English speakers are the dental clicks written with a single pipe, ⟨ǀ⟩. These are 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, or to call a cat or other animal, and is written tut! in British English and tsk! in American English. In many cultures around the Mediterranean a simple dental click is used for "no" in answer to a direct question. They are written with the letter c in Zulu and Xhosa.
• Next most familiar to English speakers are the lateral clicks, which are 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!. They are written with the letter x in Zulu and Xhosa.
• Then there are the labial clicks, written with a bull's eye, ⟨ʘ⟩. These are lip-smacking sounds, but often without the pursing of the lips found in a kiss, that occur in words in only a few languages.

The above clicks sound like affricates, in that they involve a lot of friction. The next two families of clicks 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. Something like these sounds may be used for a 'clip-clop' sound as noted above. These sounds can be quite loud. They are written with the letter q in Zulu and Xhosa.
• The palatal clicks, ⟨ǂ⟩, are made with a flat tongue that is pulled backward rather than downward, and are sharper cracking sounds than the [ǃ] clicks, like sharply snapped fingers. They are not found in Zulu but are very common in the San languages of southern Africa.
• Finally, the retroflex clicks are poorly known, being attested from only a single language, Central !Kung. The tongue is curled back in the mouth, and they are both fricative and hollow sounding, but descriptions of these sounds vary between sources. This may reflect dialect differences. They are perhaps most commonly written ⟨‼⟩, but that is an ad hoc transcription. The expected IPA letter is ⟨𝼊⟩ (⟨ǃ⟩ with retroflex tail), and the IPA supported the addition of that letter to Unicode.

Technically, these IPA letters transcribe only the forward articulation of the click, not the entire consonant. As the Handbook states,[1]

Since any click involves a velar or uvular closure [as well], it is possible to symbolize factors such as voicelessness, voicing or nasality of the click by combining the click symbol with the appropriate velar or uvular symbol: [k͡ǂ ɡ͡ǂ ŋ͡ǂ], [q͡ǃ].[2]

Thus technically [ǂ] is not a consonant, but only one part of the articulation of a consonant, and one may speak of "ǂ-clicks" to mean any of the various click consonants that share the [ǂ] place of articulation.[3] In practice, however, the simple letter ⟨ǂ⟩ has long been used as an abbreviation for [k͡ǂ], and in that role it is sometimes seen combined with diacritics for voicing (e.g. ⟨ǂ̬⟩ for [ɡ͡ǂ]), nasalization (e.g. ⟨ǂ̃⟩ for [ŋ͡ǂ]), etc. These differing transcription conventions may reflect differing theoretical analyses of the nature of click consonants, or attempts to address common misunderstandings of clicks.

Like other consonants, clicks can be described using four parameters: place of articulation, manner of articulation, phonation (including glottalisation) and airstream mechanism. As noted above, clicks necessarily involve at least two closures, which in some cases operate partially independently: an anterior articulation traditionally represented by the special click symbol in the IPA—and a posterior articulation traditionally transcribed for convenience as oral or nasal, voiced or voiceless, though such features actually apply to the entire consonant. The literature also describes a contrast between velar and uvular rear articulations for some languages.

In some languages that have been reported to make this distinction, such as Nǁng, all clicks have a uvular rear closure, and the clicks explicitly described as uvular are in fact cases where the uvular closure is independently audible: contours of a click into a pulmonic or ejective component, in which the click has two release bursts, the forward (click-type) and then the rearward (uvular) component. "Velar" clicks in these languages have only a single release burst, that of the forward release, and the release of the rear articulation isn't audible. However, in other languages all clicks are velar, and a few languages, such as Taa, have a true velar–uvular distinction that depends on the place rather than the timing of rear articulation and that is audible in the quality of the vowel.

Regardless, in most of the literature the stated place of the click is the anterior articulation (called the release or influx), whereas the manner is ascribed to the posterior articulation (called the accompaniment or efflux). The anterior articulation defines the click type and is written with the IPA letter for the click (dental ⟨ǀ⟩, alveolar ⟨ǃ⟩, etc.), whereas the traditional term 'accompaniment' conflates the categories of manner (nasal, affricated), phonation (voiced, aspirated, breathy voiced, glottalised), as well as any change in the airstream with the release of the posterior articulation (pulmonic, ejective), all of which are transcribed with additional letters or diacritics, as in the nasal alveolar click, ⟨ǃŋ⟩ or ⟨ᵑǃ⟩ or—to take an extreme example—the voiced (uvular) ejective alveolar click, ⟨ᶢǃ͡qʼ⟩.

The size of click inventories ranges from as few as three (in Sesotho) or four (in Dahalo), to dozens in the Kxʼa and Tuu (Northern and Southern Khoisan) languages. Taa, the last vibrant language in the latter family, has 45 to 115 click phonemes, depending on analysis (clusters vs. contours), and over 70% of words in the dictionary of this language begin with a click.[10]

Clicks appear more stop-like (sharp/abrupt) or affricate-like (noisy) 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, whereas labial, dental and lateral clicks typically have longer and acoustically noisier click types that are superficially more like affricates. In East Africa, however, the alveolar clicks tend to be flapped, whereas the lateral clicks tend to be more sharp.

The five click places of articulation with dedicated symbols in the International Phonetic Alphabet (IPA) are labial ʘ, dental ǀ, palatal ("palato-alveolar") ǂ, (post)alveolar ("retroflex") ǃ and lateral ǁ. In most languages, the alveolar and palatal types are abrupt; that is, they are sharp popping sounds with little frication (turbulent airflow). The labial, dental and lateral types, 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 places, ǃ and ǁ, are sometimes called "grave", because their pitch is dominated by low frequencies; whereas the laminal places, ǀ and ǂ, are sometimes called "acute", because they are dominated by high frequencies. (At least in the Nǁng language and Juǀʼhoan, 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; whereas 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 labial 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.) There are also two main conventions for the second letter of the digraph as well: voicing may be written with g and uvular affrication with x, or voicing with d and affrication with g (a convention of Afrikaans). In two orthographies of Juǀʼhoan, for example, voiced /ᶢǃ/ is written g! or dq, and /ᵏǃ͡χ/ !x or qg. In languages without /ᵏǃ͡χ/, such as Zulu, /ᶢǃ/ may be written gq.

1. ^a ⟨🡣⟩ was proposed by Clement Doke,[11] and 𝼋 by Beach,[12] but did not catch on. The former is not supported by Unicode, and the latter was proposed only in 2020. (Doke's character resembles a down arrow and is here represented by the old Roman numeral for 50;[note 3] Beach is a double-barred esh.) Three of these, ⟨ʇ⟩, ⟨ʗ⟩ and ⟨ʖ⟩, were adopted into the IPA, though eventually abandoned. Doke and Beach used additional or modified letters for voiced and nasal clicks, but they did not catch on.
2. ^b The labial and palatal clicks do not occur in written Bantu languages. However, the palatal clicks have been romanised in Naron, Juǀʼhõasi and !Xun, where they have been written ⟨tc⟩, ⟨ç⟩ and ⟨qc⟩, respectively. In the 19th century, they were sometimes written ⟨v⟩, which might be source of the Doke letter ⟨🡣⟩.

There are a few less-well-attested articulations. A reported subapical retroflex articulation ⟨𝼊⟩ in Grootfontein !Kung[note 4] turns out to be alveolar with lateral release, ⟨ǃ𐞷⟩; Ekoka !Kung has a fricated alveolar click with an s-like release, provisionally transcribed ⟨ǃ͡s⟩; and Sandawe has a "slapped" alveolar click, provisionally transcribed ⟨ǃ¡⟩ (in turn, the lateral clicks in Sandawe are more abrupt and less noisy than in southern Africa). However, the Khoisan languages are poorly attested, and it is quite possible that, as they become better described, more click articulations will be found.

Formerly when a click consonant was transcribed, two symbols were used, one for each articulation, and connected with a tie bar. This is because a click such as [ŋ͡ǂ] was 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: ⟨ŋ͡ǂ⟩ or ⟨ǂ͡ŋ⟩. However, a tie bar was not often used in practice, and when the manner is tenuis (a simple [k]), it was often omitted as well. That is, ⟨ǂ⟩ = ⟨kǂ⟩ = ⟨ǂk⟩ = ⟨k͡ǂ⟩ = ⟨ǂ͡k⟩. Regardless, elements that do not overlap with the forward release are usually written according to their temporal order: Prenasalisation is always written first (⟨ŋɡ͡ǂ⟩ = ⟨ŋǂ͡ɡ⟩ = ⟨ŋǂ̬⟩), and the non-lingual part of a contour is always written second (⟨k͡ǂʼqʼ⟩ = ⟨ǂ͡kʼqʼ⟩ = ⟨ǂ͡qʼ⟩).

However, it is common to analyse clicks as simplex segments, despite the fact that the front and rear articulations are independent, and to use diacritics to indicate the rear articulation and the accompaniment. At first this tended to be ⟨ᵏǂ, ᶢǂ, ᵑǂ⟩ for ⟨k͡ǂ, ɡ͡ǂ, ŋ͡ǂ⟩, based on the belief that the rear articulation was velar; but as it has become clear that the rear articulation is often uvular or even pharyngeal even when there is no velar–uvular contrast, voicing and nasalisation diacritics more in keeping with the IPA have started to appear: ⟨ǂ̥, ǂ̬, ǂ̃, ŋǂ̬⟩ for ⟨ᵏǂ, ᶢǂ, ᵑǂ, ŋᶢǂ⟩.

In practical orthography, the voicing or nasalisation is sometimes given the anterior place of articulation: dc for ᶢǀ and mʘ for ᵑʘ, for example.

In the literature on Damin, the clicks are transcribed by adding ⟨!⟩ to the homorganic nasal: ⟨m!, nh!, n!, rn!⟩.

Places of articulation are often called click types, releases, or influxes, though 'release' is also used for the accompaniment/efflux. There are seven or eight known places of articulation, not counting slapped or egressive clicks. These are (bi)labial affricated ʘ, or "bilabial"; laminal denti-alveolar affricated ǀ, or "dental"; apical (post)alveolar plosive ǃ, or "alveolar"; laminal palatal plosive ǂ, or "palatal"; laminal palatal affricated ǂᶴ (known only from Ekoka !Kung); subapical postalveolar 𝼊, or "retroflex" (only known from Central !Kung and possibly Damin); and apical (post)alveolar lateral ǁ, or "lateral".

Languages illustrating each of these articulations are listed below. Given the poor state of documentation of Khoisan languages, it is quite possible that additional places of articulation will turn up. No language is known to contrast more than five.

Extra-linguistically, Coatlán Zapotec of Mexico uses a linguolabial click, [ǀ̼ʔ], as mimesis for a pig drinking water,[14] and several languages, such as Wolof, use a velar click [ʞ], long judged to be physically impossible, for backchanneling and to express approval.[15] An extended dental click with lip pursing or compression ("sucking-teeth"), variable in sound and sometimes described as intermediate between [ǀ] and [ʘ], is found across West Africa, the Caribbean and into the United States.

The exact place of the alveolar clicks varies between languages. The lateral, for example, is alveolar in Khoekhoe but postalveolar or even palatal in Sandawe; the central is alveolar in Nǀuu but postalveolar in Juǀʼhoan.[16]

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 Juǀʼhoan, the alveolar click types [ǃ] and [ǁ] only occur, or preferentially occur, before back vowels, whereas the dental and palatal clicks 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 uvularised 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. The back-vowel constraint is also triggered by labial clicks, though not by labial stops. Clicks subject to this constraint involve a sharp retraction of the tongue during release.

Miller and colleagues (2003) used ultrasound imaging to show that the rear articulation of the alveolar clicks ([ǃ]) in Nama is substantially different from 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 centimetres 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].

Languages do not all behave alike. In Nǀuu, the simple clicks /ʘ, ǃ, ǁ/ trigger the [əi] and [æ] allophones of /i/ and /e/, whereas /ǀ, ǂ/ do not. All of the affricated contour clicks, such as /ǂ͡χ/, do as well, as do the uvular stops /q, χ/. However, the occlusive contour clicks pattern like the simple clicks, and /ǂ͡q/ does not trigger the back-vowel constraint. This is because they involve tongue-root raising rather than tongue-root retraction in the uvular-pharyngeal region. However, in Gǀwi, which is otherwise largely similar, both /ǂ͡q/ and /ǂ͡χ/ trigger the back-vowel constraint (Miller 2009).

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 Khoekhoe, [ǃkˀ ~ ŋˀǃk] of Sandawe and [ŋ̊ǃˀ ~ ŋǃkˀ] of Hadza may be essentially the same phone; no language distinguishes them, 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 listed on a common row 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. This may be an effect of epiglottalised voiced consonants, because voicing is incompatible with epiglottalisation.

Languages of the southern African Khoisan families only permit clicks at the beginning of a word root. However, they also restrict other classes of consonant, such as ejectives and affricates, to root-initial position. The Bantu languages, Hadza and Sandawe allow clicks within roots.

In some languages, all click consonants within known roots are the same phoneme, as in Hadza cikiringcingca /ǀikiɺiN.ǀiN.ǀa/ 'pinkie finger', which has three tenuis dental clicks. Other languages are known to have the occasional root with different clicks, as in Xhosa ugqwanxa /uᶢ̊ǃʱʷaᵑǁa/ 'black ironwood', which has a slack-voiced alveolar click and a nasal lateral click.

No natural language allows clicks at the ends of syllables or words, but then no languages with clicks allows many consonants at all in those positions. Similarly, clicks are not found in underlying consonant clusters apart from /Cw/ (and, depending on the analysis, /Cχ/), as languages with clicks do not have other consonant clusters than that. Due to vowel elision, however, there are cases where clicks are pronounced in cross-linguistically common types of consonant clusters, such as Xhosa [sᵑǃɔɓilɛ] Snqobile, from Sinqobile (a name), and [isǁʰɔsa] isXhosa, from isiXhosa (the Xhosa language).[23]

Like other articulatorily complex consonants, clicks tend to be found in lexical words rather than in grammatical words, but this is only a tendency. In Nǁng, for example, there are two sets of personal pronouns, a full one without clicks and a partial set with clicks (ńg 'I', á 'thou', í 'we all', ú 'you', vs. nǀǹg 'I', gǀà 'thou', gǀì 'we all', gǀù 'you'), as well as other grammatical words with clicks such as ǁu 'not' and nǀa 'with, and'.

One genetic study concluded that clicks, which occur in the languages of the genetically divergent populations Hadza and !Kung, may be an ancient element of human language.[24] However, this conclusion relies on several dubious assumptions (see Hadza language), and most linguists assume that clicks, being quite complex consonants, arose relatively late in human history. How they arose is not known, but it is generally assumed that they developed from sequences of non-click consonants, as they are found allophonically for doubly articulated consonants in West Africa,[25] for /tk/ sequences that overlap at word boundaries in German,[8] and for the sequence /mw/ in Ndau and Tonga.[note 12] Such developments have also been posited in historical reconstruction. 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 clicks from a large percentage of their vocabulary, presumably due to Bantu influence. As a rule, a click is replaced by a consonant with close to the manner of articulation of the click 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].

Clicks are often presented as difficult sounds to articulate within words. However, children acquire them readily; a two-year-old, for example, may be able to pronounce a word with a lateral click [ǁ] with no problem, but still be unable to pronounce [s].[26] Lucy Lloyd reported that after long contact with the Khoi and San, it was difficult for her to refrain from using clicks when speaking English.[27]

• Ladefoged, Peter (1968). A phonetic study of West African languages: An auditory-instrumental survey (2nd ed.). ISBN 0-521-06963-7.
• Ladefoged, Peter; Maddieson, Ian (1996). The Sounds of the World's Languages. Oxford: Blackwell. ISBN 978-0-631-19815-4.
• Amanda Miller, Levi Namaseb, Khalil Iskarous. 2003. Tongue Body constriction differences in click types.
• Amanda Miller, 2011. "The Representation of Clicks". In Oostendorp et al. eds., The Blackwell Companion to Phonology.
• 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.

• Collection of click-language links and audio samples.
• Hartmut Traunmüller (2003) "Clicks and the idea of a human protolanguage", Phonum 9: 1 – 4 (Umeå University, Dept. of Philosophy and Linguistics)
• Classifying clicks
• A Chinese nursery rhyme with flapped clicks (or search for videos with the words 天上一隻鵝)