Click consonants, or clicks, are speech sounds that occur as consonants in many languages of Southern Africa and in three languages of East Africa. Examples familiar to English-speakers are the tut-tut or tsk! tsk! used to express disapproval or pity, the tchick! used to spur on a horse, and the clip-clop! sound children make with their tongue to imitate a horse trotting. However, these paralinguistic sounds in English are not full click consonants, as they only involve the front of the tongue, without the release of the back of the tongue that is required for clicks to combine with vowels and form syllables.
A fricative is a consonant produced by forcing air through a narrow channel made by placing two articulators close together. These may be the lower lip against the upper teeth, in the case of ; the back of the tongue against the soft palate in the case of German ; or the side of the tongue against the molars, in the case of Welsh. This turbulent airflow is called frication.
The field of articulatory phonetics is a subfield of phonetics that studies articulation and ways that humans produce speech. Articulatory phoneticians explain how humans produce speech sounds via the interaction of different physiological structures. Generally, articulatory phonetics is concerned with the transformation of aerodynamic energy into acoustic energy. Aerodynamic energy refers to the airflow through the vocal tract. Its potential form is air pressure; its kinetic form is the actual dynamic airflow. Acoustic energy is variation in the air pressure that can be represented as sound waves, which are then perceived by the human auditory system as sound.
Postalveolar (post-alveolar) consonants are consonants articulated with the tongue near or touching the back of the alveolar ridge. Articulation is farther back in the mouth than the alveolar consonants, which are at the ridge itself, but not as far back as the hard palate, the place of articulation for palatal consonants. Examples of postalveolar consonants are the English palato-alveolar consonants, as in the words "ship", "'chill", "vision", and "jump", respectively.
The lateral clicks are a family of click consonants found only in African languages. The clicking sound used by equestrians to urge on their horses is a lateral click, although it is not a speech sound in that context. Lateral clicks are found throughout southern Africa, for example in Zulu, and in some languages in Tanzania and Namibia. The place of articulation is not known to be contrastive in any language, and typically varies from alveolar to palatal.
The alveolar or postalveolar clicks are a family of click consonants found only in Africa and in the Damin ritual jargon of Australia. The tongue is more or less concave, and is pulled down rather than back as in the palatal clicks, making a hollower sound than those consonants.
Doubly articulated consonants are consonants with two simultaneous primary places of articulation of the same manner. They are a subset of co-articulated consonants. They are to be distinguished from co-articulated consonants with secondary articulation; that is, a second articulation not of the same manner. An example of a doubly articulated consonant is the voiceless labial–velar plosive, which is a and a pronounced simultaneously. On the other hand, the voiceless labialized velar plosive has only a single stop articulation, velar, with a simultaneous approximant-like rounding of the lips. In some dialects of Arabic, the voiceless velar fricative has a simultaneous uvular trill, but this is not considered double articulation either.
The retroflex clicks are a family of click consonants known only from the Central ǃKung language or dialect of Namibia. They are sub-apical retroflex and should not be confused with the more widespread postalveolar clicks, which are sometimes mistakenly called "retroflex" due to their concave tongue shape.
Pulmonic-contour clicks, also called sequential linguo-pulmonic consonants, are consonants that transition from a click to an ordinary pulmonic sound, or more precisely, have an audible delay between the front and rear release of the click. All click types have linguo-pulmonic variants, which occur as both stops and affricates, and are attested in four phonations: tenuis, voiced, aspirated, and murmured. At least a voiceless linguo-pulmonic affricate is attested from all Khoisan languages of southern Africa, as well as (reportedly) from the Bantu language Yeyi from the same area, but they are unattested elsewhere.
The alveolar nasal click is a click consonant found primarily among the languages of southern Africa. The symbol in the International Phonetic Alphabet for a nasal alveolar click with a velar rear articulation is ⟨ŋ͡ǃ⟩ or ⟨ŋ͜ǃ⟩, commonly abbreviated to ⟨ŋǃ⟩, ⟨ᵑǃ⟩ or ⟨ǃ̃⟩; a symbol abandoned by the IPA but still preferred by some linguists is ⟨ŋ͡ʗ⟩ or ⟨ŋ͜ʗ⟩, abbreviated ⟨ŋʗ⟩, ⟨ᵑʗ⟩ or ⟨ʗ̃⟩. For a click with a uvular rear articulation, the equivalents are ⟨ɴ͡ǃ, ɴ͜ǃ, ɴǃ, ᶰǃ⟩ and ⟨ɴ͡ʗ, ɴ͜ʗ, ɴʗ, ᶰʗ⟩. Sometimes the accompanying letter comes after the click letter, e.g. ⟨ǃŋ⟩ or ⟨ǃᵑ⟩; this may be a simple orthographic choice, or it may imply a difference in the relative timing of the releases.
The voiceless or more precisely tenuis palatal click is a click consonant found primarily among the languages of southern Africa. The symbol in the International Phonetic Alphabet for a tenuis palatal click with a velar rear articulation is ⟨k͡ǂ⟩ or ⟨k͜ǂ⟩, commonly abbreviated to ⟨kǂ⟩, ⟨ᵏǂ⟩ or simply ⟨ǂ⟩. Linguists who prefer the old IPA letters use the analogous Beach convention of ⟨k͡𝼋⟩ or ⟨k͜𝼋⟩, abbreviated ⟨k𝼋⟩, ⟨ᵏ𝼋⟩ or just ⟨𝼋⟩. For a click with a uvular rear articulation, the equivalents are ⟨q͡ǂ, q͜ǂ, qǂ, 𐞥ǂ⟩ and ⟨q͡𝼋, q͜𝼋, q𝼋, 𐞥𝼋⟩. Sometimes the accompanying letter comes after the click letter, e.g. ⟨ǂk⟩ or ⟨ǂᵏ⟩; this may be a simple orthographic choice, or may imply a difference in the relative timing of the releases.
The voiced palatal click is a click consonant found among the languages of southern Africa. The symbol in the International Phonetic Alphabet for a voiced palatal click with a velar rear articulation is ⟨ɡ͡ǂ⟩ or ⟨ɡ͜ǂ⟩, commonly abbreviated to ⟨ɡǂ⟩, ⟨ᶢǂ⟩ or ⟨ǂ̬⟩. Linguists who prefer the old IPA letters use the analogous Beach convention of ⟨ɡ͡𝼋⟩ or ⟨ɡ͜𝼋⟩, abbreviated ⟨ɡ𝼋⟩, ⟨ᶢ𝼋⟩ or ⟨𝼋̬⟩. For a click with a uvular rear articulation, the equivalents are ⟨ɢ͡ǂ, ɢ͜ǂ, ɢǂ, 𐞒ǂ⟩ and ⟨ɢ͡𝼋, ɢ͜𝼋, ɢ𝼋, 𐞒𝼋⟩. Sometimes the accompanying letter comes after the click letter, e.g. ⟨ǂɡ⟩ or ⟨ǂᶢ⟩; this may be a simple orthographic choice, or it may imply a difference in the relative timing of the releases.
The palatal nasal click is a click consonant found primarily among the languages of southern Africa. The symbol in the International Phonetic Alphabet for a nasal palatal click with a velar rear articulation is ⟨ŋ͡ǂ⟩ or ⟨ŋ͜ǂ⟩, commonly abbreviated to ⟨ŋǂ⟩, ⟨ᵑǂ⟩ or ⟨ǂ̃⟩. Linguists who prefer the old IPA letters use the analogous Beach convention of ⟨ŋ͡𝼋⟩ or ⟨ŋ͜𝼋⟩, abbreviated ⟨ŋ𝼋⟩, ⟨ᵑ𝼋⟩ or ⟨𝼋̃⟩. For a click with a uvular rear articulation, the equivalents are ⟨ɴ͡ǂ, ɴ͜ǂ, ɴǂ, ᶰǂ⟩ and ⟨ɴ͡𝼋, ɴ͜𝼋, ɴ𝼋, ᶰ𝼋⟩. Sometimes the accompanying letter comes after the click letter, e.g. ⟨ǂŋ⟩ or ⟨ǂᵑ⟩; this may be a simple orthographic choice, or may imply a difference in the relative timing of the releases.
The voiceless or more precisely tenuis retroflex click is a rare click consonant. In practical orthography, an ad hoc symbol ⟨‼⟩ is used for the retroflex clicks; a tenuis click with a velar rear articulation is ⟨k͡‼⟩ or ⟨k͜‼⟩, commonly abbreviated to ⟨k‼⟩, ⟨ᵏ‼⟩ or just ⟨‼⟩. The implicit symbol in the International Phonetic Alphabet is ⟨k͡𝼊⟩ or ⟨k͜𝼊⟩, abbreviated ⟨k𝼊⟩, ⟨ᵏ𝼊⟩ or just ⟨𝼊⟩. Linguists who prefer the old IPA letters use the analogous Doke convention of ⟨k͡ψ⟩ or ⟨k͜ψ⟩, abbreviated ⟨kψ⟩, ⟨ᵏψ⟩ or ⟨ψ⟩. For a click with a uvular rear articulation, the equivalents are ⟨q͡‼, q͜‼, q‼, 𐞥‼⟩, ⟨q͡𝼊, q͜𝼊, q𝼊, 𐞥𝼊⟩ and ⟨q͡ψ, q͜ψ, qψ, 𐞥ψ⟩. Sometimes the accompanying letter comes after the click letter, e.g. ⟨𝼊k⟩ or ⟨𝼊ᵏ⟩; this may be a simple orthographic choice, or it may imply a difference in the relative timing of the releases.
The voiced retroflex click is a rare click consonant. In practical orthography, an ad hoc symbol ⟨‼⟩ is used for the retroflex clicks; a voiced click with a velar rear articulation is ⟨ɡ͡‼⟩ or ⟨ɡ͜‼⟩, commonly abbreviated to ⟨ɡ‼⟩, ⟨ᶢ‼⟩ or ⟨‼̬⟩. The implicit symbol in the International Phonetic Alphabet is ⟨ɡ͡𝼊⟩ or ⟨ɡ͜𝼊⟩, abbreviated ⟨ɡ𝼊⟩, ⟨ᶢ𝼊⟩ or ⟨𝼊̬⟩. Linguists who prefer the old IPA letters use the analogous Doke convention of ⟨ɡ͡ψ⟩ or ⟨ɡ͜ψ⟩, abbreviated ⟨ɡψ⟩, ⟨ᶢψ⟩ or ⟨ψ̬⟩. For a click with a uvular rear articulation, the equivalents are ⟨ɢ͡‼, ɢ͜‼, ɢ‼, 𐞒‼⟩, ⟨ɢ͡𝼊, ɢ͜𝼊, ɢ𝼊, 𐞒𝼊⟩ and ⟨ɢ͡ψ, ɢ͜ψ, ɢψ, 𐞒ψ⟩. Sometimes the accompanying letter comes after the click letter, e.g. ⟨𝼊ɡ⟩ or ⟨𝼊ᶢ⟩; this may be a simple orthographic choice, or it may imply a difference in the relative timing of the releases.
The retroflex nasal click is a rare click consonant. In practical orthography, an ad hoc symbol ⟨‼⟩ is used for the retroflex clicks; a nasal click with a velar rear articulation is ⟨ŋ͡‼⟩ or ⟨ŋ͜‼⟩, commonly abbreviated to ⟨ŋ‼⟩, ⟨ᵑ‼⟩ or ⟨‼̃⟩. The implicit symbol in the International Phonetic Alphabet is ⟨ŋ͡𝼊⟩ or ⟨ŋ͜𝼊⟩, abbreviated ⟨ŋ𝼊⟩, ⟨ᵑ𝼊⟩ or ⟨𝼊̃⟩. Linguists who prefer the old IPA letters use the analogous Doke convention of ⟨ŋ͡ψ⟩ or ⟨ŋ͜ψ⟩, abbreviated ⟨ŋψ⟩, ⟨ᵑψ⟩ or ⟨ψ̃⟩. For a click with a uvular rear articulation, the equivalents are ⟨ɴ͡‼, ɴ͜‼, ɴ‼, ᶰ‼⟩, ⟨ɴ͡𝼊, ɴ͜𝼊, ɴ𝼊, ᶰ𝼊⟩ and ⟨ɴ͡ψ, ɴ͜ψ, ɴψ, ᶰψ⟩. Sometimes the accompanying letter comes after the click letter, e.g. ⟨𝼊ŋ⟩ or ⟨𝼊ᵑ⟩; this may be a simple orthographic choice, or it may imply a difference in the relative timing of the releases.
Various letters have been used to write the click consonants of southern Africa. The precursors of the current IPA letters, ⟨ǀ⟩ ⟨ǁ⟩ ⟨ǃ⟩ ⟨ǂ⟩, were created by Karl Richard Lepsius and used by Wilhelm Bleek and Lucy Lloyd, who added ⟨ʘ⟩. Also influential were Daniel Jones, who created the letters ⟨ʇ⟩ ⟨ʖ⟩ ⟨ʗ⟩ ⟨ʞ⟩ that were promoted by the IPA from 1921 to 1989, and were used by Clement Doke and Douglas Beach.
A back-released click, sometimes more precisely a back-released velar click or back-released uvular click, is a click consonant found in paralinguistic use in languages across Africa, such as Wolof. The tongue is in a similar position to other click articulations, such as an alveolar click, and like other clicks, the airstream mechanism is lingual. However, unlike other clicks, the salient sound is produced by releasing the rear closure of the tongue rather than the front closure. Consequently, the air that fills the vacuum comes from behind the tongue, from the nasal cavity and the throat. Velar clicks are always voiceless and typically nasal, as nasal airflow is required for a reasonably loud production.
