Yeniseian languages in the context of "Altai-Sayan region"

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.

The Yeniseian people refers either to the modern or ancient Siberian populations speaking Yeniseian languages. Despite evidence pointing to the historical presence of Yeniseian populations throughout Central Siberia and Northern Mongolia, only the Ket and Yugh people survive today. The modern Yeniseians live along the eastern middle stretch of the Yenisei River in Northern Siberia. According to the 2021 census, there were 1,088 Kets and 7 Yugs in Russia.

Based on hydronymic data, the Yeniseians originated from the area around the Sayan Mountains and the southern tip of Lake Baikal. The known historical distribution of the Yeniseians is likely to represent a northward migration, with the modern-day Kets representing the very northernmost expansion of the language family. This migration possibly occurred as a result of the fall of the Xiongnu confederation, which, according to Alexander Vovin, is likely to have had a Yeniseian-speaking component among its ruling elite. The Jie people, a branch of the Xiongnu who established the Later Zhao state in China, are likely to have spoken a variant of Yeniseian close to Pumpokol.

Dene–Yeniseian (/dɪˈneɪ ˌjɛnɪˈseɪ.ən/, dih-NAY YEN-ih-SAY-ən) is a proposed language family consisting of the Yeniseian languages of central Siberia and the Na-Dene languages of northwestern North America.

Reception among experts has been somewhat favorable; thus, Dene–Yeniseian has been called "the first demonstration of a genealogical link between Old World and New World language families that meets the standards of traditional comparative-historical linguistics". Other linguistic scholars have deemed Dene–Yeniseian only as "plausible".

The Ket (/ˈkɛt/ KET) language, or more specifically Imbak and formerly known as Yenisei Ostyak (/ˈɒstiæk/ OSS-tee-ak), is a Siberian language long thought to be an isolate, the sole surviving language of a Yeniseian language family. It is spoken along the middle Yenisei basin by the Ket people.

The language is threatened with extinction—the number of ethnic Kets that are native speakers of the language dropped from 1,225 in 1926 to 537 in 1989. According to the latest reports from linguists, this number has since fallen to less than 30. A 2005 census reported 485 native speakers, but this number is suspected to be inflated. According to a local news source, the number of remaining Ket speakers is around 10 to 20. Another Yeniseian language, Yugh, became extinct in the 1970s.

Yugh (/ˈjuːɡ/ YOOG; Yug) is a Yeniseian language, closely related to Ket, formerly spoken by the Yugh people, one of the southern groups along the Yenisei River in central Siberia. It went extinct by 1972. It was once regarded as a dialect of the Ket language, which was considered to be a language isolate, and was therefore called Sym Ket or Southern Ket; however, the Ket considered it to be a distinct language. By the early 1990s there were only two or three nonfluent speakers remaining, and the language was virtually extinct. The 2002 census recorded 19 ethnic Yugh in all of Russia. In the 2010 census, only one ethnic Yugh was counted, also stating their proficiency in Yugh, while in the 2020 census, 7 ethnic Yugh were counted, 2 of them stating that they were speakers of Yugh.

The Kott (Kot) language (Russian: Коттский язык) is an extinct Yeniseian language that was formerly spoken in central Siberia by the banks of the Mana River, a tributary of the Yenisei river. It became extinct in the 1850s. Kott was closely related to Ket, still spoken farther north along the Yenisei river. Assan, a close relative, is sometimes considered a dialect of Kott. The term kott may be derived from Buryat qota 'town', applied to neighbouring non-pastoral peoples, including the last few Kotts.

The Siberian Turkic or Northeastern Common Turkic languages, are a sub-branch of the Turkic language family. The following table is based upon the classification scheme presented by Lars Johanson (1998). All languages of the branch combined have approximately 670,000 native and second language speakers, with most widely spoken members being Yakut (c. 450,000 speakers), Tuvan (c. 130,000 speakers), Northern Altai (c. 57,000 speakers) and Khakas (c. 29,000 speakers). Despite their usual English name, two major Turkic languages spoken in Siberia, Siberian Tatar and Southern Altai, are not classified as Siberian Turkic, but are rather part of the Kipchak subgroup. Many of these languages have a Yeniseian substratum.