Eurasiatic is a proposed language macrofamily that would include many language families historically spoken in northern, western, and southern Eurasia. The idea of a Eurasiatic superfamily dates back more than 100 years. Joseph Greenberg's proposal, dating to the 1990s, is the most widely discussed version. In 2013, Mark Pagel and three colleagues published what they believe to be statistical evidence for a Eurasiatic language family. The branches of Eurasiatic vary between proposals, but typically include Altaic (Mongolic, Tungusic and Turkic), Chukchi-Kamchatkan, Eskimo–Aleut, Indo-European, and Uralic—although Greenberg uses the controversial Uralic-Yukaghir classification instead. Other branches sometimes included are the Kartvelian and Dravidian families, as proposed by Pagel et al., in addition to the language isolates Nivkh, Etruscan and Greenberg's "Korean–Japanese–Ainu". Some proposals group Eurasiatic with even larger macrofamilies, such as Nostratic; again, many other professional linguists regard the methods used as invalid. History of the concept In 1994 Merritt Ruhlen claimed Eurasiatic is supported by the existence of a grammatical pattern "whereby plurals of nouns are formed by suffixing -t to the noun root ... whereas duals of nouns are formed by suffixing -k." Rasmus Rask noted this grammatical pattern in the groups now called Uralic and Eskimo–Aleut as early as 1818, but it can also be found in Tungusic, Nivkh (also called Gilyak) and Chukchi–Kamchatkan—all of which Greenberg placed in Eurasiatic. According to Ruhlen, this pattern is not found in language families or languages outside Eurasiatic. In 1998, Joseph Greenberg extended his work in mass comparison, a methodology he first proposed in the 1950s to categorize the languages of Africa, to suggest a Eurasiatic language. In 2000, he expanded his argument for Eurasiatic into a full-length book, Indo-European and Its Closest Relatives: The Eurasiatic Language Family, in which he outlines both phonetic and grammatical evidence that he feels demonstrate the validity of language family. The heart of his argument is 72 morphological features that he judges as common across the various language families he examines. Of the many variant proposals, Greenberg's has attracted the most academic attention. Greenberg's Eurasiatic hypothesis has been dismissed by many linguists, often on the ground that his research on mass comparison is unreliable. The primary criticism of comparative methods is that cognates are assumed to have a common origin on the basis of similar sounds and word meanings. It is generally assumed that semantic and phonetic corruption destroys any trace of original sound and meaning