The hypothetical ancestral language of the Nostratic family is called Proto-Nostratic. Proto-Nostratic would have been spoken between 15,000 and 12,000 BCE, in the Epipaleolithic period, close to the end of the last glacial period.
The Nostratic hypothesis originates with Holger Pedersen in the early 20th century. The name "Nostratic" is due to Pedersen (1903), derived from the Latin nostrates "fellow countrymen". The hypothesis was significantly expanded in the 1960s by Soviet linguists, notably Vladislav Illich-Svitych and Aharon Dolgopolsky, termed the "Moscovite school" by Bomhard (2008, 2011, and 2014), and it has received renewed attention in English-speaking academia since the 1990s.
The hypothesis is controversial and has varying degrees of acceptance amongst linguists worldwide. In Russia, it is endorsed by a minority of linguists, such as Vladimir Dybo, but is not a generally accepted hypothesis. Allan Bomhard is a supporter, Lyle Campbell a critic. Some linguists take an agnostic view. Eurasiatic, a similar grouping, was proposed by Joseph Greenberg (2000) and endorsed by Merritt Ruhlen: it is taken as a subfamily of Nostratic by Bomhard (2008).
These proposals were taken much further in 1903 when Holger Pedersen proposed "Nostratic", a common ancestor for the Indo-European, Finno-Ugric, Samoyed, Turkish, Mongolian, Manchu, Yukaghir, Eskimo, Semitic, and Hamitic languages, with the door left open to the eventual inclusion of others.