a group of languages found only in Africa in which clicks function as normal consonants. The sole report outside Africa of a language using clicks involves the special case of Damin, a ritual vocabulary of the Lardil of northern Queensland, Australia.

While clicks are an extensive and original feature of the Khoisan languages, they have spread through linguistic contacts into a number of other languages of the Bantu (Bantu languages) and Cushitic (Cushitic languages) groups. These languages are therefore full-fledged click languages but derivatively so. In all click languages, clicks form only a portion—though sometimes the main portion—of the total number of consonants of the language. Very distinctive sounds, clicks are articulated in the mouth by a suction mechanism that produces either a sharp popping or smacking sound between the tongue and the roof of the mouth or a sucking sound between the lips (the kiss click) or teeth or at the side of the mouth. Most Khoisan languages use four clicking sounds; the Southern languages use a fifth, the “kiss” click, as well. Gciriku and Yei, which are Bantu languages of Botswana and Namibia, have incorporated the four-click Khoisan system, but Zulu (Zulu language) and Xhosa (also Bantu languages) have incorporated only three clicks. Dahalo, a Cushitic language of Kenya, uses only one click. In some Khoisan languages two of the clicks have been gradually replaced with acoustically similar nonclick consonants, which in effect has produced a two-click system.

Clicks are used extensively in the vocabulary of Khoisan languages, and they are the initial sounds in approximately 70 percent of the words. This lends a dramatic effect to running speech. Clicks are extremely salient sounds perceptually and therefore are ideally adapted to transmitting a language. Their exotic nature and uniqueness has invited speculation that they may be associated with special meanings, but this is not the case.