Overtone Voices
Six sounds from one throat: Tuvan, Mongolian, Tibetan and Inuit. Five are overtone singing; the last is a vocal game that only sounds like it.
None of these are learned from notation — each is passed mouth to mouth, over years. Tuvan and Mongolian herders often sing to open land and animals as much as to people; the Gyuto chant is liturgical; katajjaq is historically a women's game, played while the men were away hunting.