Sounds common in Khosian languages of South Africa that are produced by sudden release of a closure of a large area of the tongue against the palate. These languages are made up of three branches: the Khoisan languages of the San (Bushmen) and Khoikhoi, spoken in various parts of sub-Saharan Africa, Sandawe, found in Tanzania, and Hatsa (Hadzane or Hadzapi), also in Tanzania. Although all the Khoisan languages use click sounds, Sandawe and Hatsa are unlike the other Khoisan languages and are not related to each other. All of the Khoisan languages appear to use tones to distinguish meanings, and the Khoikhoi languages and some of the San languages inflect the noun to show case, number, and gender. However, the outstanding feature of the Khoisan languages is their extensive use of click sounds. Examples of click sounds familiar to speakers of English are the interjection tsk-tsk and the clip clop used to signal to a horse. The sounds, which are found only in Africa as parts of words, involve a sucking action by the tongue, but as well the position of the tongue and the way in which air is released into the mouth vary, just as in the formation of other sounds. Consequently, clicks can be dental, palatal, alveolar, lateral, labial, or retroflex; voiced, voiceless, or nasal; aspirated or glottal. There are six types of clicks for the San languages, although no single one has all of them. The Khoikhoi languages have dental, palatal, retroflex, and lateral clicks. Some Bantu languages, notably Zulu and Xhosa, which are spoken near the Khoisan area, have borrowed click sounds from the Khoisan languages. Nothing seems to be known about how click sounds are incorporated into speech development. It must be a complicated process as there are more than 100 ways to begin a word with a click.
See Fricative, Glottal, Labio-dental, Language development, Lateral sound, Lingua-alveolar (or alveolar), Lingua-dental (or dental), Lingua-palatal (or palatal), Liquid, Plosive