Ejective-contour clicks, also called sequential linguo-glottalic consonants, are consonants that transition from a click to an ejective sound, or more precisely, have an audible delay between the front and rear release of the click. All click types (alveolar , dental , lateral , palatal , retroflex , and labial ) have linguo-glottalic variants, which occur as both stops and affricates, and may be voiced. At least a voiceless linguo-glottalic affricate is attested from all Khoisan languages of southern Africa (the Khoe, Tuu, and Kx'a language families), as well as from the Bantu language Yeyi from the same area, but they are unattested elsewhere.