In 1994,
Merritt Ruhlen asserted that a Eurasiatic language could be supported by a specific grammatical pattern involving distinct suffixes for plural and dual noun forms, which does not appear in languages outside the proposed Eurasiatic superfamily. However, the pattern itself had been observed long before, as Rasmus Rask had already described it in 1818 within the
Uralic and
Eskimo–Aleut groups. 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.
Stefan Georg and
Alexander Vovin, who, unlike many of their colleagues, do not stipulate
a priori that attempts to find ancient relationships are bound to fail, examined Greenberg's claims in detail. They state that Greenberg's morphological arguments are the correct approach to determining families, but doubt his conclusions. They write "[Greenberg's] 72 morphemes look like massive evidence in favour of Eurasiatic at first glance. If valid, few linguists would have the right to doubt that a point has been made [...] However, closer inspection [...] shows too many misinterpretations, errors and wrong analyses [...] these allow no other judgement than that [Greenberg's] attempt to demonstrate the validity of his Eurasiatic has failed." In the 1980s, Russian linguist 's hypothesis () linked the
Indo-European,
Uralic,
Turkic,
Mongolic, and
Tungusic language families, including
Koreanic in his later papers. Andreev also proposed 203 lexical roots for his hypothesized Boreal macrofamily. After Andreev's death in 1997, the Boreal hypothesis was further expanded by
Sorin Paliga (2003, 2007).
Pagel et al. In 2013,
Mark Pagel, Quentin D. Atkinson, Andreea S. Calude, and Andrew Meade published statistical evidence that attempts to overcome these objections. According to their earlier work, most words exhibit a "
half-life" of between 2,000 and 4,000 years, consistent with existing theories of linguistic replacement. However, they also identified some words – numerals, pronouns, and certain adverbs – that exhibit a much slower rate of replacement with half-lives of 10,000 to 20,000 or more years. Drawing from research in a diverse group of modern languages, the authors were able to show the same slow replacement rates for key words regardless of current pronunciation. They conclude that a stable core of largely unchanging words is a common feature of all human discourse, and model replacement as inversely proportional to usage frequency. Words were separated into groupings based on how many language families appeared to be cognate for the word. Among the 188 words, cognate groups ranged from 1 (no cognates) to 7 (all languages cognate) with a mean of 2.3 ± 1.1. The distribution of cognate class size was
positively skewed − many more small groups than large ones − as predicted by their hypothesis of variant decay rates. Twenty-three word meanings had cognate class sizes of four or more. The authors write "Our ability to predict these words independently of their sound correspondences dilutes the usual criticisms leveled at such long-range linguistic reconstructions, that proto-words are unreliable or inaccurate, or that apparent phonetic similarities among them reflect chance sound resemblances." On the first point, they argue that inaccurate reconstructions should weaken, not enhance, the signals. On the second, they argue that chance resemblances should be equally common across all word usage frequencies, in contrast to what the data shows. The team then created a
Markov chain Monte Carlo simulation to estimate and date the
phylogenetic trees of the seven language families under examination. Five separate runs produced the same (unrooted) tree, with three sets of language families: an eastern grouping of Altaic, Inuit–Yupik, and Chukchi–Kamchatkan; a central and southern Asia grouping of Kartvelian and Dravidian; and a northern and western European grouping of Indo-European and Uralic. The first roots the tree to the midpoint of the branch leading to proto-Dravidian and yields an estimated origin for Eurasiatic of 14450 ± 1750 years ago. The second roots the tree to the proto-Kartvelian branch and yields 15610 ± 2290 years ago. Internal nodes have less certainty, but exceed chance expectations, and do not affect the top-level age estimate. The authors conclude "All inferred ages must be treated with caution but our estimates are consistent with proposals linking the near concomitant spread of the language families that comprise this group to the retreat of glaciers in Eurasia at the end of the last ice age ~15,000 years ago." Writing on University of Pennsylvania blog
Language Log,
Sarah Thomason questions the accuracy of the LWED data on which the paper was based. She notes that LWED lists multiple possible proto-word reconstructions for most words, increasing the possibility of chance matches. Pagel
et al. anticipated this criticism and state that since infrequently used words generally have more proposed reconstructions, such errors should "produce a bias in the opposite direction" of what the statistics actually show (i.e. that infrequently used words should have larger cognate groups if chance alone was the source). Thomason also argues that since the LWED is contributed to primarily by believers in
Nostratic, a proposed superfamily even broader than Eurasiatic, the data is likely to be biased towards proto-words that can be judged cognate. Pagel
et al. also examined two other possible objections to their conclusions. They rule out
linguistic borrowing as a significant factor in the results on the basis that for a word to appear cognate in many language families solely because of borrowing would require frequent swapping back and forth. This is deemed unlikely because of the large geographical area covered by the language groups and because frequently-used words are the least likely to be borrowed in modern times. ==Classification==