therefore easy to defend; the reasons for its survival elsewhere are unclear. Ruhlen argues that Eurasiatic is supported by stronger and clearer evidence than Dené–Caucasian, and that this also indicates that the spread of Dené–Caucasian occurred before that of Eurasiatic. The existence of a Dené–Caucasian family is disputed or rejected by some linguists, including Lyle Campbell, Ives Goddard, and Larry Trask. The last common ancestor of the family was estimated by phylogenetic analysis of ultraconserved words at roughly 15,000 years old, suggesting that these languages spread from a "refuge" area at the Last Glacial Maximum. See also Ancient North Eurasian#Comparative mythology Indo-Semitic languages Indo-Uralic languages Nostratic languages Proto-Human language Ural–Altaic languages Uralo-Siberian languages Notes The 23 words are (listed in order of cognate class size): Thou (7 cognates), I (6), Not, That, To give, We, Who (5), Ashes, Bark, Black, Fire, Hand, Male/man, Mother, Old, This, To flow, To hear, To pull, To spit, What, Worm, Ye (4) References Greenberg, Joseph H. 1957. Essays in Linguistics. Chicago: University of Chicago Press. Greenberg, Joseph H. 2000. Indo-European and Its Closest Relatives: The Eurasiatic Language Family. Volume 1, Grammar. Stanford: Stanford University Press. Greenberg, Joseph H. 2002. Indo-European and Its Closest Relatives: The Eurasiatic Language Family. Volume 2, Lexicon. Stanford: Stanford University Press. Greenberg, Joseph H. 2005. Genetic Linguistics: Essays on Theory and Method, edited by William Croft. Oxford: Oxford University Press. Mithun, Marianne. 1999. The Languages of Native North America. Cambridge: Cambridge University Press. Nichols, Johanna. 1992. Linguistic Diversity in Space and Time. Chicago: University of Chicago Press. Further reading Bancel, Pierre J.; de l'Etang, Alain Matthey. "The millennial persistence of Indo-European and Eurasiatic pronouns and the origin of nominals". In: In Hot Pursuit of Language in Prehistory: Essays in the four fields of anthropology. In honor of Harold Crane Fleming. Edited by John D. Bengtson. John Benjamins Publishing Company, 2008. pp. 439–464. https://doi.org/10.1075/z.145.32ban External links NorthEuraLex "Indo-Uralic and Altaic" by Frederik Kortlandt (2006) Regions Based on Social Structure: A Reconsideration Altaic languages Eskaleut languages Etruscan language Paleosiberian languages Proposed language families Uralic languages