The Khoisan, or Click, linguistic family is made up of three branches: the Khoisan languages of the San (Bushmen) and Khoikhoi, spoken in various parts of sub-Saharan Africa; Sandawe, a language found in E Africa; and Hatsa (Hadzane or Hadzapi), also spoken in E Africa. Although all the Khoisan languages use click sounds, Sandawe and Hatsa are unlike the other Khoisan tongues and are not related to each other. All of the Khoisan languages appear to use tones to distinguish meanings, and the Khoikhoi languages and some of the San languages inflect the noun to show case, number, and gender. The outstanding characteristic of the Khoisan tongues, however, is their extensive use of click sounds. (Examples of click sounds familiar to speakers of English are the interjection tsk-tsk and the click used to signal to a horse.) Click sounds, which are found only in Africa as parts of words, involve a sucking action by the tongue, but the position of the tongue and the way in which air is released into the mouth vary, just as in the formation of other sounds; thus clicks may be dental, palatal, alveolar, lateral, labial, or retroflex; voiced, voiceless, or nasal; aspirated or glottal. Six types of clicks are known for the San languages as a whole, although no single tongue has all of them. The Khoikhoi languages have dental, palatal, retroflex, and lateral clicks. Some Bantu languages, notably Zulu and Xhosa, which are spoken near the Khoisan area, have borrowed click sounds from the Khoisan languages.