Ket is the last surviving member of the Yenisei family of languages and is spoken by about 550 people along the Yenisei River and its tributaries in Central Siberia.
Ket is also known as Yenisei-Ostiak and Ostyganna qa' and is related to Yugh or Yug, which died in the 1970s, and Pumpokol, Arin and Kot, which became extinct during the 18th and 19th centuries. These languages are thought by some linguists to be related to the North-Caucasian and Sino-Tibetan languages; and by others, such as Edward Vajda, a historical linguist at Western Washington University, to the Na-Dené languages of North America, although the tonal system of Ket is closest to Vietnamese.
This spelling system using the Latin alphabet was developed in the 1920s and 1930s by N.K. Karger, who publised the first Ket alphabet primer.
This Cyrillic-based system was developed in the 1980s by G.K. Verner and G.H. Nikolayeva.