Ket is the last surviving member of the Yenisei family of languages. It is spoken along the Yenisei River and its tributaries in Central Siberia. In 2010 there were 210 speakers. The majority of speakers were older adults, and few Ket speakers were raising their children to speak the language. There were no known monolingual speakers. In 2017 there were no remaining fluent Ket speakers.
Ket is also known as Yenisei-Ostiak or Ostyganna qa'. It is related to Yugh or Yug, which became extinct 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. Others, such as Edward Vajda, a historical linguist at Western Washington University, believe they are related to the Na-Dené languages of North America.
Ket is taught as a subject in some primary schools up to the fourth grade. After that only Russian is taught.