Atlas of Pidgin and Creole Language Structures Online

While only a few languages in southern Africa have click sounds (velaric ingressive consonants) in ordinary words, many languages can use clicks as para-linguistic, interjection-like gestures. This feature follows WALS feature 142, by David Gil.

Such usages of clicks are not systematically described by linguists, but they show interesting patterns. In some languages, clicks may have only logical meanings, i.e. ‘no’ or ‘yes’. In others, they may have only affective meanings, i.e. meanings such as disapproval, surprise, or disdain. English is such a language (the alveolar click is sometimes spelled “tsk” or “tut”). There are also languages where clicks can have both logical and affective meanings, and finally, some languages do not have para-linguistic clicks at all.

(Click sounds are consonants that are articulated with two closures in the oral cavity. After the pocket of air enclosed between these two closures is rarefied by a sucking action of the tongue, the release of the forward closure produces the characteristic click sound; phoneticians describe clicks as having velaric ingressive airstream mechanism.)