According to UNESCO's 2010 edition of the Atlas of the World’s Languages in Danger, there are 148 endangered languages in the Russian Federation. The list does not include number of languages from bordering countries such as Belarusian and Ukrainian languages. An endangered language is a language that it is at risk of falling out of use, generally because it has few surviving speakers. If it loses all of its native speakers, it becomes an extinct language.
UNESCO defines four levels of language endangerment between "safe" (not endangered) and "extinct":
References
List of endangered languages in Russia Wikipedia(Text) CC BY-SA