コイサン語族
"Khoisan" is a term of convenience covering some 30 languages spoken by around 300,000–400,000 people. There are five Khoisan families that have not been shown to be related to each other: Khoe, Tuu and Kx’a, which are found mainly in Namibia and Botswana, as well as Sandawe and Hadza of Tanzania, which are language isolates. A striking feature of Khoisan languages, and the reason they are often grouped together, is their use of click consonants. Some neighbouring Bantu languages (notably Xhosa and Zulu) have clicks as well, but these were adopted from Khoisan languages. The Khoisan languages are also tonal.