Kott language in the context of "Yenisei river"

A language isolate, or an isolated language, is a language that has no demonstrable genetic relationship with any other languages. Basque in Europe, Ainu and Burushaski in Asia, Sandawe in Africa, Haida and Zuni in North America, Kanoê and Trumai in South America, and Tiwi in Oceania are all examples of such languages. The exact number of language isolates is yet unknown due to insufficient data on several languages.

One explanation for the existence of language isolates is that they might be the last remaining member of a larger language family. Such languages might have had relatives in the past that have since disappeared without being documented, leaving them an orphaned language. One example is the Ket language spoken in central Siberia, which belongs to the wider Yeniseian language family; had it been discovered in recent times independently from its now extinct relatives, such as Yugh and Kott, it would have been classified as an isolate. Another explanation for language isolates is that they arose independently in isolation and thus do not share a common linguistic genesis with any other language but themselves. This explanation mostly applies to sign languages that have developed independently of other spoken or signed languages.

Assan (Russian: Ассанский язык) is an extinct Yeniseian language spoken to the south of Krasnoyarsk in Russia. It went extinct in the 18th century. It is similar enough to the Kott language that it can be regarded as a dialect of it, but the Assan identified as a separate ethnicity from the Kotts.

Before its extinction, in 1735-1740, there were two to three speakers of Assan.