FWIW, from http://www.kalahari-meerkats.com/fileadmin/files/guides/Bushmen_light.pdf http://www.kalahari-meerkats.com/fileadmin/files/guides/Bush... : Bushmen

FWIW, from http://www.kalahari-meerkats.com/fileadmin/files/guides/Bushmen_light.pdf http://www.kalahari-meerkats.com/fileadmin/files/guides/Bush... : Bushmen speak a variety of languages, all of which incorporate 'click' sounds represented in writing by symbols such as ! or /. The unique clicks used in Khoisan languages are varied and complex, with many varieties and applications throughout the different Clans and groups. Here is a very simplified description of the more common ones used. They are denoted by internationally recognised symbols. • / (Forward slash) - denotes a frontal dental click similar to the English "Tsk-Tsk" of disapproval. /? is a Glottal variation & ?/ is a nasal type. • // (2 Forward slashes) - denotes a lateral dental click similar to the sound used to urge a horse. • ≠ (Equals sign bisected by a forward slash, “not-equal sign”) - denotes a sharp alveolar click made with the tongue against the roof of the mouth. • ! (Exclamation mark) - denotes a sharp palato-alveolar click made with the tongue on the back of the gum ridge. Cork popping sound.