Dukha (3196) = Endangered (100 percent certain, based on the evidence available) ("Today, all Dukhans are bilingual in Dukhan and Darkhat Mongolian... all Dukhans over 30 years of age are bilingual in Dukhan and Darkhat Mongolian. They use one idiom or the other depending on the addressee. Dukhans between 20 and 30 years of age have various degrees of Dukhan proficiency, depending on the internal structure of the family. Dukhans between 15 and 20 years of age tend to use Mongolian for all spheres of communication, even if they, in many instances, master Dukhan perfectly. Dukhan below 15 years of age speak only Darkhat Mongolian, but have a passive knowledge of Dukhan. Their Dukhan speech is strongely adapted to Mongolian constructions.
Within the Dukhan community, there are many households where parents speak more Mongolian than Dukhan with their children. In mixed families, where one of the parents is Mongol, the children rarely master Dukhan. Only in rare cases do Mongols who are married to a Dukhan-speaking person learn the language...
Finally, it should be pointed out that the use of Dukhan is more common in the taiga areas, whereas it is decreasing in the river areas and in the village of Tsagaan-Nuur." (p.31-32))
Glottolog
Dukha at Endangered Languages Project
Wikipedia
Wikidata