A typology of the use of clicks

Abstract

Click speech sounds were first identified as consonants in the 17th century. On his voyage to India in 1627, the English traveller and historian Sir Thomas Herbert stopped in southern Africa, where he met with Khoekhoe speakers at the Cape. He noticed that clicks were regular consonants in their language and represented them as such in his travelogue (Herbert 1638). Since then, click consonants have received thorough scholarly attention by linguists, many of whom have dedicated their lives to the study of click consonants. Click speech sounds are consonants in phoneme inventories of about 301 of the approximately 6,5002 languages spoken in the world today. These few languages, henceforth referred to as click-consonant-using (CU) languages, are found in southern and eastern Africa. In this squib we propose a typology of the different uses of click speech sounds in human communication.

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© 2023 The authors. This work is licensed under the Creative Commons Attribution 4.0 International License.
Stellenbosch Papers in Linguistics Plus, Vol. 67, 2023, 59-77
doi: 10.5842/67-1-1007
A typology of the use of clicks
Matthias Brenzinger
Department of African Languages, University of the Free State, South Africa
E-mail: mabrenzinger@gmail.com
Sheena Shah
Department for Language, Literature and Culture, TU Dortmund University, Germany
Department of African Languages, University of the Free State, South Africa
E-mail: sheena.shah@tu-dortmund.de
1. Introduction
Click speech sounds were first identified as consonants in the 17th century. On his voyage to
India in 1627, the English traveller and historian Sir Thomas Herbert stopped in southern
Africa, where he met with Khoekhoe speakers at the Cape. He noticed that clicks were regular
consonants in their language and represented them as such in his travelogue (Herbert 1638).
Since then, click consonants have received thorough scholarly attention by linguists, many of
whom have dedicated their lives to the study of click consonants. Click speech sounds are
consonants in phoneme inventories of about 301 of the approximately 6,5002 languages spoken
in the world today. These few languages, henceforth referred to as click-consonant-using (CU)
languages, are found in southern and eastern Africa.
Click consonants are complex speech sounds. According to Miller (2011:416),
Clicks exhibit at least three major areas of complexity that are not found in most
other consonants: (1) the double place of articulation features; (2) the overlap of
the two constrictions for the length of the segments; and (3) the non-pulmonic
airstream mechanism.
Click consonants are distinguished by their click type (e.g., bilabial, dental, lateral, etc.) with
reference to the front constriction. A second, back constriction in the basic click production is
either velar or uvular (Sands 2020:3). When these constrictions are released, an ingressive
airstream makes the “characteristic popping sound” (Miller 2011:416) or “suction noise known
1 This number varies as some scholars include languages with few click-containing words, such as Cicopi or
Rukwangali, to the list of click-consonant-using languages, while others do not.
2 Figures for the total number of languages of the world vary significantly. 6,500 (Hammarström 2016) is a more
conservative estimate. The 25th edition of the Ethnologue lists 7,151 languages (Eberhard, Simons & Fennig 2022),
while the Glottolog (4.6) catalogue lists 8,565 languages (Hammarström, Forkel, Haspelmath & Bank 2022).

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as a click” (Sands 2020:2). This ingressive airflow produced by the movements of the tongue
is the main source of noise in the production of click consonants (Sands 2020:3). Click
consonants are furthermore identified by their accompaniments (e.g., voicing, aspiration,
nasalisation, glottalisation, etc.)3.
Many non-CU languages use non-phonemic clicks. These speech sounds have often been called
“para-linguistic clicks”, for example by Gil (2013). Gil (2013) defines the “para-linguistic”
nature of such clicks as follows:
Phonetically, they [para-linguistic clicks] involve sounds lying outside ordinary
phonemic inventories. Grammatically, they are not integrated into
morphological and syntactic structures. And semantically, they convey a very
restricted range of meanings, some of which are associated with the expression
of emotions.
While click consonants are employed in less than 0.5% of the world’s languages, non-
phonemic, non-consonantal clicks4 seem to be rather common throughout the world, “with
people sometimes leap[ing] to the assumption that they are universal” (Gil 2013). The use of
these non-consonantal clicks is, however, very limited, as they appear exclusively in
interactives. This applies not only to non-CU languages, but also to CU languages. Heine
defines interactives as “extra-clausal expressions of linguistic discourse”, which “have a
grammar distinct from sentence grammar, referred to as interactive grammar” (Heine 2023:
back cover).
The above-mentioned term “para-linguistic clicks” is not appropriate for at least two reasons.
First, “para-linguistic” suggests that these clicks are “alongside language … not within it”
(Pillion et al. 2019:304, emphasis added), thus downplaying the importance of the interactive
grammar in communication. Grenoble, Martinović and Baglini (2015:112) rightfully state that
“the term paralinguistic is misleading in that some […] gestures, including Gil’s yes/no clicks,
substitute for lexical items and so are not truly paralinguistic but linguistic.” Second, the notion
of “para-linguistic clicks” is even more problematic with CU languages, as they do not employ
additional non-consonantal clicks as “para-linguistic clicks” in or as interactives. Instead, they
commonly5 use click consonants which are members of their phoneme inventories, also in the
interactive grammar (in Gil’s terms, “paralinguistically”).
Non-consonantal clicks in non-CU languages, but also click consonants in CU languages, often
appear in the interactive grammar as click-only utterances, i.e., as click speech sounds without
accompanying vowels. While standalone click consonants or sequences of click consonants
violate the phonotactic constraints of word formation in the sentence grammar of CU languages
(Güldemann & Nakagawa 2018), these clicks nevertheless remain true phonemes of these CU
languages as they are employed as regular consonants in the sentence grammar otherwise6.
3 For a detailed description of the production of click consonants, see Sands (2020).
4 While all non-consonantal clicks are non-phonemic, not all non-phonemic clicks are non-consonantal, as
discussed in our typology below.
5 In Section 3, we discuss the only example of a non-consonantal click used as an interactive in a CU language
which is known to us.
6 Similarly, the affricate pf [pf] in German as a singleton may be used as an interjection signalling disapproval of
a statement made by someone else. While the utterance of a standalone affricate pf violates the constraints of word
formation in the German sentence grammar, pf is at the same time also used as a consonant in German lexemes

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Click phoneme inventories, and consequently the use of click consonants, are language-
specific, as is the use of non-consonantal clicks. This means that the same click speech sound,
for example, a voiceless lateral click consonant x, is a regular click consonant in isiXhosa in
the interjection expressing disappointment but is a non-consonantal click when used in English
as an interjection encouraging a horse to trot.
Non-consonantal clicks were detected and studied already as early as the 19th century, for
example as click interjections in French (Ballu 1868), and continue to receive scholarly
attention, for example as click discourse markers in English (Wright 2011). Nevertheless, non-
consonantal clicks in contrast to click consonants have been studied far less systematically in
terms of their production and use in the world’s languages. The approaches applied to study
non-consonantal clicks and click consonants belong to different research traditions which, until
recently, seem to have taken little notice of each other. This has changed in some respects with
research conducted on non-consonantal clicks in the West African language, Wolof (Grenoble
et al. 2015), and the Chadian language, Laal (Lionnet 2020), as well as on the tongue pop, a
non-consonantal click employed by drag queens in several unrelated lavender languages
(Pratchett 2021).
In terms of their production, Bradfield (2014:3) claims that all five click types represented in
the International Phonetic Alphabet are also used as non-consonantal clicks. The large number
of click accompaniments which have been described for click consonants in some of the CU
languages seems, however, not to be utilised with non-consonantal clicks. These clicks seem to
be less complex in this regard as they tend to be plain clicks, i.e., voiceless and unaspirated.
Proctor et al. (2020:229) state that “we do not yet know if all clicks produced for paralinguistic
purposes have equivalents in phonological systems”. What we do know, however, is that some
of the speech sounds in the interactive grammar which are referred to as “clicks” are not
employed as consonants in any CU languages. Among them are also speech sounds which do
not comply with the basic features described in the production of click consonants and which
might therefore be more appropriately labelled as “click-like articulations” (Lionnet 2020:422).
Lionnet (2020) observes that several of the non-consonantal clicks and “non-phonemic click-
like articulations” which he reports for Laal, a language isolate of Chad, are shared among West
and Central African languages more widely. For example, one of the click-like speech sounds,
described by Lionnet (2020:427–432) for Laal as a “back-released velar click”, is used as a
backchanneling strategy to express approval also in Wolof (see also Pillion et al. 2019). In terms
of its production, this click-like speech sound shares several features with click consonants,
such as the non-pulmonic airstream mechanism, the back and front closures, and the tongue
movement which plays an important role in the sound production. There are, however, two
significant differences between this click-like speech sound and non-consonantal clicks/click
consonants. First, there is full lip closure throughout the sound production, i.e., the front
constriction is not released. Second, instead of the front closure being released, as described for
all click consonants, it is the velaric back closure which is released, and the airstream enters the
mouth from the back (Lionnet 2020:427–432). Our use of the generic terms “clicks”/“click
such as Pferd ‘horse’ and Pfeife ‘pipe’. The affricate pf in the interjection is – at least to our knowledge – not a
different, additional speech sound but the regular consonant of the German phoneme inventory. We assume that
the same applies with CU languages, i.e., that click speech sounds which are employed as click-only interactives
are regular consonants of the phoneme inventory.

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speech sounds” is based on the definition of the production of click consonants (see Miller 2011
above). In order for speech sounds to be called clicks, we expect that even non-consonantal
clicks share at least the basic features identified in the production of click consonants. Since
this is not the case with the so-called “back-released velar click”, the term “non-phonemic click-
like articulation” rather than “non-consonantal click” seems more appropriate.
In the following, we propose a typology of the different uses of click speech sounds in human
communication.
2. A typology of the use of clicks
Click consonants seem to have the longest history in the languages of the Kx’a, Tuu and Khoe-
Kwadi families in southern Africa as well as in the linguistic isolates Hadza and Sandawe7 in
eastern Africa (Güldemann 2014). While click consonants are not part of the shared phonemic
heritage of the Bantu language family, about half of today’s CU languages are Bantu languages
spoken in southern Africa. These Bantu languages borrowed click-containing words from
languages of the Kx’a, Tuu and Khoe-Kwadi families or from each other. In some of these
Bantu languages, click phonemes became regular consonants of “standard” phoneme
inventories. A few – most likely also borrowed – click-containing words are found in Dahalo,
an endangered Cushitic language spoken in Kenya. The use of click consonants is confined to
this small number of CU languages8.
The proposed typology in Table 1 attempts to account for all uses of click speech sounds that
occur in the languages of the world. At the first level, two categories are distinguished, namely
click consonants and non-consonantal clicks, with the former being confined to CU languages
only and the latter being almost exclusively documented for non-CU languages. At the second
level, two subcategories of click phonemes are identified, namely regular and non-regular click
consonants. The non-regular consonants are further subcategorised into remnant, borrowed and
special click consonants. Non-consonantal clicks are set apart in a separate category. Since click
inventories vary across languages and may change over time, it is important to note that the
proposed typology can only be applied to one specific language at one point in time.
Table 1 below summarises the main properties associated with click consonants and the
different subcategories thereof on the one hand and with non-consonantal clicks on the other.
7 Sandawe is often considered to be a potential higher-order relative of Khoe-Kwadi (Güldemann & Elderkin
2010).
8 Individual click-containing words have, however, been borrowed by a few non-CU languages through contact
with CU languages. See discussion in Section 2.2.

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Table 1. Typology of the use of clicks
Categories
Click consonants
(mostly in CU languages)
Non-consonantal clicks
(mostly in non-CU
languages)
Subcategories of
click phonemes
Regular
(current)
Irregular
Not phonemes
(1)
Remnant
(former)
(2)
Borrowed
(new)
(3)
Special
(for example,
conventionalised
mouthpiece)
Part of “standard”
phoneme inventories
Yes
No longer
Not yet
No
Speech sound
inventories
“Standard”
phoneme
inventories
“Extended” phoneme inventories9
“Extended” speech sound
inventories
Phonetic and
articulatory
properties
Complex speech sounds defined by click type (influx) &
click accompaniment (formerly efflux); exceptions exist
Less complex speech
sounds, occurring mostly
as plain clicks with click
accompaniments often
not distinctive
Sentence grammar
Consonants in word formation
Not employed
Interactive grammar
Consonants in word formation, also as standalone or
sequences of consonants
Employed mainly as
standalone or sequences
of non-consonantal clicks
Semantic domains,
functions
All
Limited
domains
Limited domains, limited
functions
2.1 Regular click consonants
CU languages are identified by their use of click consonants. The significance of click
phonemes, however, differs considerably among the approximately 30 CU languages. In
determining the functional load of click consonants10 of a particular CU language, two
parameters are commonly considered (Güldemann 2007; Sands & Gunnink 2019; Brenzinger
& Shah forthcoming):
• the complexity of the click inventories, i.e., the number of distinct click consonants;
• the frequency of the occurrence of click consonants in the lexicon of the language.
Regarding the first parameter, numbers of distinct click consonants vary significantly among
the CU languages: the Tuu language, Taa, with its 115 click consonants (Naumann 2016), has
the largest click consonant inventory among the CU languages, while CU Bantu languages,
with between 27 click phonemes in Botswanan Shiyeyi (Sommer 2003) and three in Sesotho
(Doke & Mofokeng 1957), are at the lower end of this scale11. Regarding the second parameter,
the frequency of click consonants in the vocabularies of CU languages ranges from about 80%
in Taa (i.e., eight out of ten words begin with click consonants) to below 1% in the Kavango
Bantu languages (Brenzinger & Shah forthcoming).
9 The term “extended” phoneme inventory must be taken with some caution as non-regular click consonants might
through their distinct properties form a sub-group of click consonants in the click consonant inventory of a
language and as such not simply “extend” the “standard” phoneme inventory.
10 The term “functional load” in reference to click phonemes was introduced by Güldemann (2007).
11 See Brenzinger and Shah (forthcoming) for a detailed discussion of the functional load of click phonemes in CU
languages.

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One distinct click type and one specific click accompaniment can commonly be identified with
each click consonant. This binary assignment is also reflected in the written representation. For
example, in the case of the voiced dental click consonant [ǀɡ], the dental click type is transcribed
with the IPA click symbol [ǀ], which orthographies represent as either 〈ǀ〉 or 〈c〉. The voicing
accompaniment is commonly transcribed with [ɡ] or [ɡ] in IPA and with 〈g〉 or 〈d〉 in most
orthographies.
Linguists commonly group click consonants according to their click type, assigning them to a
bilabial, dental, palatal, etc., click series. At least in some CU languages, speakers also seem to
arrange click consonants in this manner. For example, Taa speakers use verbs with the meaning
‘to produce a click consonant of the X click type’12. There are no comparable verbs in Taa for
referring to click consonants with the same click accompaniments, i.e., *‘to produce a click
consonant with a nasal, delayed aspiration, etc.’. Nevertheless, in Taa, as well as in all other
CU languages, click accompaniments are distinctive features and as important as click types in
the production and perception of a particular click consonant.
In fact, in some of the CU languages, click consonants are primarily defined by their click
accompaniment and not by their click type. In these languages, click accompaniments remain
steady while click types are less salient; the latter are chosen indifferently among speakers but
also by the same speaker. Maddieson (2003:37) observes, with regard to click consonants in
some languages, a “lack of respect for place [of articulation] when few categorical contrasts
exist” and states that “such context-free liberty to vary place of articulation is rarely encountered
with other classes of consonants”. For this “lack of respect for place [of articulation]” with click
consonants, he cites examples from Xinkuna (Xitsonga) (Baumbach 1974), Thimbukushu
(Fisch 1977) and Rugciriku (Möhlig 1997).
In the Kavango languages Thimbukushu und Rumanyo (Rugciriku), click consonants are
distinguished according to their accompaniments as “voiceless”, “voiced”, “voiceless
nasalised”, “voiced nasalised”, and “prenasalised voiceless dental clicks with pharyngeal
efflux” (Möhlig & Shiyaka-Mberema 2005:26). Möhlig (1997:219) notes for Rukwangali,
another Kavango language, that “there are five distinctive clicks. Their places of articulation
are almost all dental, however, with a broad individual variation … they are rare phonemes,
which is a system internal indication of their foreign origin.” Click consonants in the Kavango
languages might never have been adopted in their entire complexity, i.e., click types might have
been pronounced interchangeably already at the time when the borrowing from Khoe-Kwadi or
Kx’a languages took place.
The fading distinctiveness between click types can also be observed in isiNdebele, formerly
known as Southern Transvaal Ndebele. Schulz et al. (2019:251) observe that dental clicks
prevail in this language, noting that these dental clicks may be pronounced as postalveolar
clicks. This “lack of respect for the place [of articulation]” might be the result of either click
loss or click replacement. More recently, these processes seem to have come to a halt in
isiNdebele; in fact, they might even be reversed as a result of contact with isiXhosa speakers
and through writing isiXhosa at school. Due to exposure to a language with a more “complete”
12 ʘhùũ-ʘhùũ & ʘnùũ-ʘnùũ ‘make the sound of the bilabial click [ʘ]’ (Traill 1994:50, 51); ǀhèẽ-ǀhèẽ & ǀ’àa-ǀ’àa
‘make the sound of the dental click’ (Traill 1994:66, 71); ǃhèẽ-!hèẽ ‘make the sound of the [!] click’ (Traill
1994:90); ǁnàa-ǁnàa & ǁ’àã-ǁ’àã ‘make the sound of the lateral click [ǁ]’ (Traill 1994:122, 128); ǂhèẽ-ǂhèẽ & ǂ’èẽ-
ǂ’èẽ ‘make the sound of the [ǂ] click’ (Traill 1994:144, 150).

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Nguni click consonant inventory, especially younger isiNdebele speakers are increasingly
pronouncing click consonants with their “correct, original” click types and accompaniments
(Schulz et al. 2019:253).
2.2 Remnant and borrowed click consonants
In CU languages – as well as in some non-CU Bantu languages which are in contact with CU
Bantu languages – click consonants may appear in the lexicon despite the fact that they are not
part of the “standard” phoneme inventory. These other click consonants may have been regular
click phonemes in the past and are now relic, remnant click consonants, i.e., first subcategory
of non-regular click consonants (see Table 1 above). They may, however, also be new click
consonants which have been borrowed in loanwords, i.e., second subcategory.
In the case of remnant click consonants, some click-containing words may have preserved click
consonants which are no longer in use in the language otherwise. In Sindebele, formerly known
as Northern Transvaal Ndebele, all click consonants have disappeared over the last 100 years
or so; hence, this language is no longer listed among the CU languages. The last click
consonants in Sindebele – then already remnant click consonants – seem to have been used in
plant names. Ziervogel (1959:33) reports for the mid-1950s:
My old informants remember former times when the old people actually used
clicks in their speech. Actually, some plant names are still known by names with
click sounds, […]
In the case of borrowed click consonants, additional click consonants that are not otherwise
used in the language may enter a CU language with loanwords. SiSwati, for example, has
borrowed click-containing isiZulu words and maintained their “original” pronunciation, even
with words which contain click consonants that are not part of the siSwati phoneme inventory.
The borrowed verb kúnconcótsa ‘to pound, hammer, ram’, which derives from the borrowed
click-containing ideophone ncó13, is such an example. While rendered 〈nc〉, i.e., using the
common representation for a nasal dental click consonant in the Nguni writing convention, both
the ideophone and the derived verb are, according to Rycroft (1982:67), pronounced with a
“prenasalized postalveolar click”; they should therefore be written as kúnqonqótsa and nqó,
respectively. Click consonants of the postalveolar click type are not part of the “standard”
phoneme inventory of siSwati, but through borrowing became new click consonants of the
language.
When non-CU languages borrow click-containing words, these click consonants become part
of an “extended” phoneme inventory, even if these click-containing words are interjections. For
example, in Setswana and Northern Sotho, languages which do not employ click consonants
otherwise, “clicks are used emotionally, for example in interjections” (Herbert 2002:307). No
examples are provided by Herbert, and these click interjections might therefore be non-
consonantal clicks like in other non-CU languages. However, if the click-containing
interjections have been borrowed from neighbouring CU languages, the click speech sounds
would be borrowed click consonants.
13 ncó ‘1. Ideophone of knocking […]. 2. of being erect, upright, vertical. 3. of sloping upwards steeply’ (Rycroft
1982:67).

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While the borrowing of click consonants by non-CU languages in southern Africa is quite
common, it seems to occur only rarely in eastern Africa. One of the few examples of the latter
is found at the Kenyan coast, where a “complex click” in an interjection has been documented
in dialects of Digo, one of the Mijikenda languages. Walsh (2006:159) mentions this click,
which he sets apart from other “simple unelaborated clicks [which] do occur in Digo
interjections”. He notes that a “voiced velar nasal” dental click consonant followed by the vowel
“a” – in his transcription /ᵑǀa/ – functions as an interjection which expresses “(perhaps rudely)
driving someone away” (Walsh 2006:116). Dahalo, a Cushitic language that most likely
borrowed click-containing words from CU languages which no longer exist, is spoken in the
vicinity of Digo (Brenzinger & Shah forthcoming). One may assume a similar origin for /ᵑǀa/ in
Digo, namely a borrowing of an interjection which consists of a click consonant with an
accompanying vowel.
If non-CU languages borrow click-containing words in large numbers, the status of these
languages might be reconsidered. For example, Xitsonga and Cicopi are often regarded as CU
languages due to extensive borrowing of click-containing isiZulu words (Brenzinger & Shah
forthcoming). Accordingly, the borrowed click consonants – even though limited to loans –
become part of the “extended” phoneme inventories of these formerly non-CU languages.
The origin of non-regular click phonemes is not always transparent, as seen in the following
examples from Ts’ixa and Namibian Shiyeyi. For Ts’ixa, a Kalahari Khoe language, Andrason,
Fehn and Phiri (2020) and Fehn and Ketapilwe (2021) provide examples of words with both
remnant and borrowed click consonants, see Table 2.
Table 2. Non-regular click consonants in Ts’ixa ideophones
Click consonant
Ideophone
Gloss
Source
(1)
!x’
Alveolar affricate
ejective click consonant
!x’ua
Sound made by a
large stone falling
into the water
Andrason, Fehn &
Phiri (2020:311, fn.
25)
(2)
ǂk’
Palatal voiceless ejective
click consonant
ǂk’upiǂk’upi
Sound of leaking
rainwater
Fehn & Ketapilwe
(2021:72)
(3)
ǀ’h
Dental click with delayed
aspiration
ǀ’hup
Sound with which a
tuber is pulled out
Fehn & Ketapilwe
(2021:70)
While the three click consonants in Table 2 are not part of the Ts’ixa phoneme inventory, they
are regular click consonants in neighbouring languages. Fehn (p.c. 2021) suggests different
scenarios for these non-regular click phonemes in Ts’ixa: limited retention of the click
consonants [!x’] (1) and [ǂk’] (2), i.e., they formerly existed as regular click consonants which
were replaced by non-click speech sounds elsewhere in the lexicon, and introduction of a new
click consonant by means of borrowing in the case of [ǀ’h] (3).
A non-regular click consonant also exists in Namibian Shiyeyi, a CU Bantu language spoken
in the Zambezi region of the country. Even though Shiyeyi has no lateral click consonants in
its phoneme inventory, Donnelly (1990:14) describes an “alveo-lateral … [ǁ]” click consonant
in an “interjection expressing disapproval”. He also notes a verb which is derived from this
interjection, namely kùnql’ápìzá meaning ‘to indicate disapproval by making the interjection
[ǁ]’. Seidel (2008:43) later describes the click as “voiceless pre-nasal lateral” and he also notes
a derived verb kùnxàpìzá [kun
ǁapiza] ‘disapprove by making a lateral click’. For the time being,

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the question remains open as to whether the lateral click existed in Namibian Shiyeyi in the
past, thus making it a remnant click consonant, or whether this lateral click consonant entered
the language through borrowing of this interjection from another CU language, thus making it
a borrowed and therefore new click consonant.
2.3 Special click consonants
In addition to remnant and borrowed click consonants, there are other non-regular click
phonemes which can be subsumed under the label “special click consonants”. In this discussion,
we focus on and introduce one special click consonant, namely the “conventionalised
mouthpiece click consonant”14. Conventionalised mouthpiece click consonants are click speech
sounds which are produced by speakers who serve as mouthpiece by speaking on behalf of a
particular animal or another non-human entity; thus, storytellers are not imitating the non-
humans but make their presumably genuine voices speaking the human language heard.
Such special click phonemes have been described in the animal speeches of Damin, a ritual
register used by Lardil-speaking males on the Mornington Islands in Australia. In the 1970s,
Ken Hale documented this register with the last proficient speaker. Damin used to be taught to
male initiates and had many speech sounds which occur rarely or not at all in the languages of
the world. Claimed to be produced by “an ancestor known as Kaltharr (Yellow Trevally Fish),
[Damin] has a rich inventory of sounds, some echoing what ‘fish talk’ would sound like” (Evans
2010:201). Among these sounds are also “Khoisan-style clicks” (Evans 2010:246), such as a
“nasalized bilabial click” in the word m!ii [ŋ
ʘi:] which corresponds to a proto-Tangkic word
*miyi ‘vegetable food’, the latter being without the click (Evans 2010:201). It seems that Damin
– and for that reason also the use of these special click consonants – was limited to certain
ceremonial contexts.
Conventionalised mouthpiece click consonants were already described in the 1870s by Wilhelm
Bleek and Lucy Lloyd when they recorded stories in ǀXam, a Tuu language once spoken by
hunter-gatherers, which became extinct in the late 1920s. When animals or the moon appear in
these stories and speak ǀXam, the storytellers become their mouthpiece. The narrators
pronounce ǀXam in the way in which they anticipate the words would sound like if uttered by
these animals or the moon. While non-click consonants in Damin are replaced by click
consonants and other speech sounds when imagining how “‘fish talk’ would sound like”, ǀXam
speakers replace click consonants from the “standard” ǀXam click phoneme inventory with
special click consonants from an “extended” ǀXam click phoneme inventory. Bleek (1875:6)
notes:
A most curious feature in Bushman folklore is formed by the speeches of various
animals, recited in modes of pronouncing Bushman [ǀXam], said to be peculiar
to the animals in whose mouth they are placed. It is a remarkable attempt to
imitate the shape or position of the mouth of the kind of animal to be represented.
Among the sounds which are hereby affected, and often entirely commuted, are
principally the clicks.
14 The term “conventionalised mouthpiece click consonant” is a newly coined label, which has been suggested by
Bernhard Weiss (p.c. 2022).

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Although ǀXam speakers were already using 37 regular click consonants (Güldemann 2013:82),
Bleek (1875:6) noticed that the moon, the anteater, and the hare employ “a most
unpronounceable click” which is otherwise not used in the language. When the moon talks
ǀXam, Bleek observed that the regular click consonants are substituted with those from the
“moon click series” with the exception of the bilabial click consonants which are retained.
In ǀXam, the special click consonants in the speeches of animals and non-human entities are
conventionalised in that they are defined by specific click types. These non-regular click types
are joined by the regular click accompaniments of the “standard” ǀXam click series. Bleek
represents the additional click types with distinct click symbols and employs the established
writing conventions for the representation of the click accompaniments. ǀXam children most
likely acquired these conventionalised mouthpiece click consonants naturally, just like any
other click consonants of their language. In contrast to the click consonants in Damin which
were used by males in specific contexts only, the conventionalised mouthpiece click consonants
in ǀXam seem to have been part of an “extended” click phoneme inventory and were employed
by all ǀXam speakers when speaking on behalf of the moon, hare and anteater.
The existence of these additional click types in ǀXam led Bleek (1875:6) to suggest that:
The presence of these abnormal clicks in the different kinds of speech, points to
the possibility, nay, even to the probability, of the former presence of many more
clicks in the Bushman language than the five [click types] which are now to be
found there.
Bleek’s assertion that ǀXam might have had an even richer click phoneme inventory in the past
does not, however, necessarily imply that the animal and moon click consonants were once
click phonemes of the “standard” phoneme inventory of ǀXam as spoken by humans.
2.4 An “impossible” speech sound used as a click consonant?
In this section, we introduce a click from Taa which at first sight appears to be another special
click consonant, however, as demonstrated by its phonetic description, it is not. As in many
other languages, Taa derives bird names from the songs of these birds. Tuhuse and Traill
(1999:1041) devoted a short paper to the names of the Desert cisticola (Cisticola aridula), a
pale brown small bird, which is called ǂhán-ǂhánsè, with a regular aspirated palatal click
consonant. The authors call this “the ‘tame’ version of the sound symbolistic form [of the bird
name] since it involves a mapping of salient acoustic features of the bird’s call onto
conventional phonological segments and prosody of the [Taa] language”. In addition, there is
also “a ‘wild’, or direct imitation of the birdsong, [which] involves a wholly unusual sound in
the place of the conventional click” (Tuhuse & Traill 1999:1041):
This sound is also an acute, impulse-like click with the identical double
articulation and suction cavity found with the palatal click, but […] it is produced
when the dorsal closure is released while maintaining the anterior (coronal)
closure. […] the articulation is probably best known as the non-linguistic gesture
used by some people to scratch an itchy velum!

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This speech sound seems in some respect to resemble the “click-like articulation” described by
Lionnet (2020) for several West African languages, e.g., the anterior closure is not released.
Tuhuse and Traill (1999:1041) provide convincing arguments which show that this “dorsally
released click” [ǂ*] “is not a possible speech sound” and therefore does “not exist in any
language”. Having stated that, they nevertheless provide a “semi-wild” version of this bird
name [ŋǂ*ńŋǂ*ńsè], which uses this “impossible” speech sound “in a conventional phonetic and
prosodic context” (Tuhuse & Traill 1999:1041). According to its description, [ǂ*] is not a
possible speech sound, but at the same time it appears as a click consonant in a bird’s name.
Our typology of the use of clicks does not accommodate for non-speech sounds which at the
same time can be employed as click consonants.
2.5 Non-consonantal clicks in non-CU languages
Following our discussion on the use of various sub-categories of click consonants by CU
languages, we now turn to the use of non-consonantal clicks. Non-consonantal clicks almost
exclusively occur in non-CU languages and our discussion in this section therefore focuses on
this set of languages only (for a discussion on the use of non-consonantal clicks in CU
languages, see Section 3).
All click speech sounds in non-CU languages are non-consonantal clicks which therefore
cannot join with phonemes to form words in the sentence grammar. Non-consonantal clicks
only appear in or as interactives and have been observed widely in non-CU languages (see Gil
2013 for examples). Already some 150 years ago, voiceless dental non-consonantal clicks were
noticed by Charles Darwin (1872:286), who mentioned that Australians and Europeans
“express gentle surprise by a little clicking noise”. Traill (1978:138), among many others, points
out that a sequence of “lateral clicks” is used in English to encourage horses to trot. Non-
consonantal clicks are commonly singletons or sequences of click-only utterances and seem to
be mainly voiceless.
As claimed by Bradfield (2014:3), all five click types represented in the International Phonetic
Alphabet, i.e., bilabial, dental, lateral (alveolar), alveolar and palatal, also occur as non-
consonantal clicks in non-CU languages. Click interjections in non-CU languages which
convey particular emotional states or attitudinal stances seem to be click type sensitive. In
contrast, click discourse markers of different functions15, at least in non-CU languages such as
English and Spanish, seem to employ click types interchangeably (Wright 2011; Pinto & Vigil
2018).
Non-consonantal clicks might take on a range of different functions within the interactive
grammar. The tongue pop used by drag queens in various Englishes, but also in Hebrew and
Thai, is used as an interjection, a discourse marker and an intensifier (Pratchett 2021). Pratchett
(2021) describes the tongue pop as follows: a “single ingressive ‘click’ consonant: appears to
be plain, laminally produced post-alveolar-to-palatal click, i.e., not a proto-typical palatal click
(ǂ)”. The tongue pop is a recent innovation and has appeared without contact to CU languages.
15 Non-consonantal clicks in English serve, for example, as discourse markers which “demarcate the onset of new
and disjunctive sequences” (Wright 2011:224).

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3. Clicks in interactives in CU languages
CU languages in contrast to non-CU languages employ click consonants not only in the
sentence grammar but also in the interactive grammar, mainly in ideophones, as discourse
markers and in primary as well as secondary interjections.
Non-consonantal clicks seem to be absent in ideophones16 in both non-CU languages and CU
languages. However, click consonants are quite often employed in ideophones by CU
languages, such as Ts’ixa (Fehn & Ketapilwe 2021), siSwati (Rycroft 1982) and !Xóõ (Taa)
(Traill 1994).
Clicks as discourse markers have not yet been systematically studied in CU languages.
However, Christian Rapold, in a personal communication with Bonny Sands in 2013, mentions
that a “voiceless palatal click occurs as a marker of the start of a turn in the speech of some
Khoekhoe women” (Sands 2020:45). Further research would be needed to confirm if other
click-containing discourse markers in CU languages, assuming that they exist, also use click
consonants, or if non-consonantal clicks can be identified in this function.
Click consonants occur regularly in interjections. Among the 343 interjections documented in
isiXhosa by Andrason and Dlali (2020), 40 interjections contain click consonants. By far most
of these click-containing interjections are made up of click consonants which are joined by
vowels, such as in camagu ‘interjection of apologizing’ (177)17, gcadinja ‘interjection of
annoyance’ (172) and qash-qash ‘interjection of surprise’ (172). There are also click-only
interjections such as nc-nc-nc-nc-nc ‘interjection of denying, rejecting, disagreeing’ (176, 185,
187) and x ‘interjections of disappointment, contempt, impatience’ (172). While these
singletons – also when repeated in a sequence – violate phonotactic constraints of the word
formation in the sentence grammar of isiXhosa, they continue to be click consonants of the
established phoneme inventory of this language.
With regard to interjections, scholars commonly distinguish between primary and secondary
interjections (Bloomfield 1914; Ameka 1992; Heine 2023). Primary interjections, such as
“oops!”, “wow” and “hmm” in English, are utterances which occur exclusively in the
interactive grammar, i.e., they carry no meaning in the sentence grammar. In contrast,
secondary interjections, such as “shit!”, “Jesus!”, “help!” or “yes!”, are interjections which
derive from homophonous nouns, verbs or other word-classes; thus, these interjections have
their origin in the sentence grammar. While all (click) speech sounds in secondary interjections
are consonants of the phoneme inventory of the language, also primary interjections, such as
nc-nc-nc-nc-nc and x mentioned above for isiXhosa, use regular (click) phonemes of the
languages in question.
In non-CU languages, there are no click-containing words from which click-containing
secondary interjections can be derived; thus, all click-containing interjections in these
languages are primary interjections. CU languages, by contrast, employ click consonants in
both primary and secondary interjections. For example, !Xun, a Kx’a language spoken
predominantly in Namibia, uses the interjections !áín ‘(a) thank you!: (b) goodbye!’ and !àn hŋ

16 “An ideophone is an interactive used for a vivid depiction of sensory imagery of a state, event, object, or quality”
(Heine 2023:148).
17 Page numbers in Andrason and Dlali (2020).

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‘wait and see!’ (König & Heine 2008:80–81). The utterance !áín exists in the sentence grammar
as a verb ‘to thank’ and !àn hŋ
 employs the two verbs ‘to wait’ and ‘to see’. For the !Xun
interjection ǁxàá ‘oh!, exclamation of surprise’ (König & Heine 2008:101), no source lexeme
has been identified yet; it might therefore be either a primary interjection or a secondary
interjection.
With click-only interjections, i.e., utterances which consist of standalone click consonants,
distinguishing between primary and secondary interjections is challenging. For example, the
voiceless lateral click consonant X18, in the meaning ‘of disappointment, impatience, etc. leave
me!’ in isiXhosa, might derive from another more complex secondary interjection Xa
 ‘Stop!’
(Kropf & Godfrey 1915:464). This would make the standalone click consonant X a secondary
interjection derived from another secondary interjection Xa
19. However, an alternative
interpretation of this example would be that the click consonant X is a primary interjection
which constituted the basis from which the more complex secondary interjection Xa
 has been
derived. If no source lexeme has (yet) been identified, it seems impossible to determine whether
an interjection in a CU language is a primary or secondary interjection.
The only example of a non-consonantal click in a CU language which is known to us has been
noted for siSwati by Rycroft (1982:8). He describes an “atypical dental click” that is not part
of the siSwati phoneme inventory and is not employed in the lexicon otherwise. This non-
consonantal click is among several click-only interjections, with all other interjections
employing click consonants from the “standard” and “extended” phoneme inventories of
siSwati, see Table 320.
Table 3. Click-only interjections in siSwati (Rycroft 1982)
Example
Click-only
interjections
Meaning of interjection
Page
(1)
c
‘of indifference or disgust (often made with tongue-tip against an eye-
tooth, rather than centrally as for the normal C click).’
8
(2a)
c c c
‘of regret: What a shame!’
9
(2b)
c c c
‘of annoyance or impatience: What a nuisance!’
9
(3)
c c
‘interj. of delight. (Usually a post-alveolar click, as Zulu Q. ...)’
9
(4a)
c
‘of annoyance (usually a lateral + velar click is used, like Zulu X). …’
8
(4b)
nx
‘(nasalised lateral click …) of annoyance or disgust’
75
While example (1) is a non-consonantal click, all other interjections in Table 3 employ either
regular or borrowed click consonants. For the two interjections (2a) and (2b) rendered 〈c c c〉,
no information on the actual pronunciation has been provided by Rycroft (1982:9). Based on
their spelling, one may assume that these sequences are three regular voiceless dental click
consonants, and even though they cannot in their current form be joined with non-click
18 In the original source, the two interjections appear as “X !” and “Xa
 !”. The exclamation marks have been
removed in the text to avoid confusion with the (post)alveolar click consonant.
19 A verb “ukuti-Xa
 … to pause, wait a little, to stop (at a place)” (Kropf & Godfrey 1915:464) has been derived
from this interjection.
20 Note that the orthographic representations by Rycroft do not adequately capture the actual pronunciation of the
click speech sounds.

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phonemes to form words, voiceless dental click consonants are part of the phoneme inventory
and are therefore regular click consonants in siSwati.
The interjection (3) 〈c c〉 in the meaning ‘of delight’ is pronounced as a “post-alveolar click”
repeated twice (Rycroft 1982:9). In the Nguni writing convention, these click consonants would
be represented as 〈q q〉 and in IPA as [! !]. Post-alveolar click consonants occur in siSwati as
(new) click phonemes in loanwords only. A verb (kú)-n
cán
cata, which expresses delight by
repeating a post-alveolar click (Rycroft 1982:66), has been derived from this click-only
interjection in which the voiceless postalveolar click consonants have received nasal
accompaniments.
Examples (4a) 〈c〉 and (4b) 〈nx〉 ‘of annoyance or disgust’ (Rycroft 1982:75) are click
consonants which seem to be – even with nasalisation lacking in (4a) – different spellings of
the same interjection with a “nasalised lateral click”. The primary interjection 〈nx〉 in siSwati
employs a new click consonant which has been borrowed from Zunda Nguni languages (see,
for example, Andrason and Dlali 2020:172, who document 〈nx〉 as a primary interjection of
anger, displeasure, and impatience in isiXhosa). Although lateral click consonants are not part
of the siSwati “standard” phoneme inventory, a verb (kú)-n
capha, expressing ‘annoyance or
impatience by uttering the lateral click’ has nevertheless either been derived from this
interjection (4a) or been borrowed from neighbouring languages (4b).
It is highly unlikely that the “atypical dental click” (1) described for siSwati is the only non-
consonantal click used by a CU language. More attention needs to be given to the actual
pronunciation of click speech sounds in interactives of CU languages in order to identify
possible non-consonantal clicks in these languages.
Click-like speech sounds employed exclusively in the interactive grammar by CU languages,
might, however, as with the examples discussed for non-CU West African languages in Section
1 above, also be “non-phonemic click-like articulations” (Lionnet 2020:422). In their study of
onomatopoeias in Tjwao, a moribund Eastern Kalahari Khoe language, Andrason, Fehn and
Phiri (2020:301) record tokens which mainly consist of regular phonemes, among them also
click consonants. One of the exceptions is a potential candidate for a non-consonantal click,
i.e., a sequence of three “bilabial clicks” 〈mbh-mbh-mbh〉 as an animal call addressed to cattle
(Andrason, Fehn & Phiri 2020:311)21. The authors state that this “non-speech sound” is “similar
to a lip-smacking sound produced in English when mimicking a fish” (Andrason, Fehn & Phiri
2020:311, fn. 25). An acoustic analysis of this speech sound by expert linguists does not yet
exist to our knowledge. Based on the description provided by the authors, there seems to be no
release of a back closure, and even more importantly, no tongue movement seems to be
involved in the sound production. Both are essential in the production of click consonants and
one may therefore refrain from referring to this lip-smacking sound as a bilabial (non-
consonantal) click. Together with whistles22, the bilabial “lip-smacking sound” belongs to an
“extended” speech sound inventory of the language which appears in the interactive grammar
only. While we can assume that non-phonemic click-like speech sounds also exist in
interactives of CU languages, they have not yet been mentioned for these languages.
21 While bilabial click phonemes are regular consonants in Taa, Nǀuu, ǂ’Amkoe, and non-regular click consonants
in Hadza, Tjwao does not have bilabial click consonants in its phoneme inventory.
22 Whistling seems to be widely employed in interactives, for example by fans in soccer stadiums to demonstrate
support or express disappointment or by humans to convey various orders when communicating with animals.

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4. Summary
Click speech sounds are widely employed as non-consonantal clicks in interjections and as
discourse markers of the interactive grammar in the languages of the world. Click consonants,
by contrast, are phonemes in only a few languages, all of which are spoken on the African
continent. Depending on the phoneme inventory, the same click speech sound can be a click
consonant in one language and a non-consonantal click in another. For example, the two
voiceless dental clicks <tsk-tsk> [ǀ ǀ] expressing disapproval are non-consonantal clicks in
English, while the same click speech sound repeated three times <c c c> [ǀ ǀ ǀ] conveying
annoyance are regular click consonants in siSwati (see Table 3).
The proposed typology presented in this paper aims at accommodating the different uses of
clicks and may be applied to specific languages, with most categories of the typology being
relevant for the 30 or so CU languages only. In the typology, click consonants and non-
consonantal clicks are first distinguished, with the former consisting of regular and non-regular
click consonants. Non-regular click phonemes can be further subcategorised into remnant click
consonants on the one hand and new click consonants which enter the language through
borrowing on the other. Special click consonants are additional non-regular click phonemes,
such as the conventionalised mouthpiece animal and moon click consonants of ǀXam. The click
consonants of these three non-regular click phoneme subcategories are members of an
“extended” phoneme inventory. The discussion of an “impossible” click-like speech sound used
as a click consonant demonstrates the limitations of the proposed typology. All clicks in non-
CU languages are non-consonantal clicks, as they are not part of the phoneme inventories of
the respective languages; they occur in interactives only. Non-consonantal clicks are
conventionalised and belong to established “extended” speech sound inventories.
While CU languages seem to utilise their often rich click consonant inventory also in
interactives, non-consonantal clicks have, with one exception, not yet been mentioned in these
languages. This might partly be because non-consonantal clicks have to date received little
scholarly attention in studies of CU languages. Further research by phoneticians specialised in
CU languages is required to determine if the click speech sounds in click-only utterances are
the regular click consonants of the respective CU languages, or if they are additional non-
consonantal clicks. While there is no denying that non-consonantal clicks are common in the
world’s languages, this does not seem to be the case with CU languages; whether non-
consonantal clicks are universal or not therefore remains an open question.
Acknowledgements
Lenore Grenoble asked many years ago if speakers of CU languages also use clicks in verbal
gestures, and this paper started off as an attempt to address her question. We are extremely
grateful to Alexander Andrason, Anne-Maria Fehn, Bernd Heine and Pippa Skotnes for
inspiring discussions on the topic and valuable feedback on previous versions of this paper. We
would also like to thank colleagues at the International Symposium on Kalahari Basin Area
Languages and Cultures in Riezlern, Austria (17th – 21st July 2022) for their constructive
comments on our typology. Thanks to Bernhard Weiss for suggesting the term
“conventionalised mouthpiece click consonant”. Many thanks also to the anonymous reviewers
for their helpful suggestions and to the editors, Ian Bekker and Theresa Biberauer, for their
professional support.

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