Group of perhaps 115 African languages spoken by more than 27 million people from Mali to Ethiopia and from southernmost Egypt to Tanzania. The concept of Nilo-Saharan as a single stock combining a number of earlier groupings was introduced in 1963 by Joseph H. Greenberg; most Africanists accepted it as a working hypothesis, though shifts have taken place. In terms of numbers of speakers, the most significant divisions of Nilo-Saharan languages include Central Sudanic, Fur, Nilotic, Nubian, Saharan, Songhai, and Surmic. Songhai is spoken by more than 2 million people in Mali and Niger, and Kanuri (a Saharan language) is spoken by about 4.5 million in northeastern Nigeria and adjacent Chad and Niger. Central Sudanic comprises languages of southern Chad, southern Sudan, and northeastern Congo (Kinshasa). Nubian languages (including the only Nilo-Saharan language with an ancient written tradition) are spoken along the Nile in northern Sudan and southern Egypt. The Nilotic languages are spoken by some 14 million people (see Nilotes), including the Dinka, Nuer, Luo, Turkana, Kalenjin, and Masai