The voiceless or more precisely tenuis (post)alveolar click is a click consonant found primarily among the languages of southern Africa. The symbol in the International Phonetic Alphabet that represents this sound is ⟨ǃ⟩. The Doke/Beach convention, adopted for a time by the IPA and still preferred by some linguists, is ⟨ʗ⟩.
The airstream mechanism is lingual ingressive (also known as velaric ingressive), which means a pocket of air trapped between two closures is rarefied by a "sucking" action of the tongue, rather than being moved by the glottis or the lungs/diaphragm. The release of the forward closure produces the "click" sound. Voiced and nasal clicks have a simultaneous pulmonic egressive airstream.