Sergei Anatolyevich Starostin (; March 24, 1953 â September 30, 2005) was a Russian historical linguist and philologist, perhaps best known for his reconstructions of hypothetical proto-languages, including his work on the controversial Altaic theory, the formulation of the DenéâÂÂCaucasian hypothesis, and the proposal of a Borean language family of still earlier date. None of his proposed macrofamilies have seen wide-scale acceptance in the linguistic community and are mostly seen as implausible.
In 1986, Starostin and Igor M. Diakonoff suggested that the Hurro-Urartian languages belong to the Northeast Caucasian language family. Starostin also helped with reconstructions Proto-Kiranti, Proto-Tibeto-Burman, Proto-Yeniseian, Proto-North-Caucasian, and Proto-Altaic. He also expanded the hypothesis that Japanese is related to the Turkic and Mongolic languages through an "Altaic" family.
The DenéâÂÂCaucasian hypothesis proposes that Northwest Caucasian, Northeast Caucasian, Yeniseian, Sino-Tibetan, and Na-Dené form a single, higher-order language family. According to Starostin, the DenéâÂÂCaucasian as well as two other proposed macrofamilies, Austric and Nostratic, can further be linked at an earlier stage, which Starostin called the Borean (i.e. 'Northern') languages.
Since 1985, Starostin had been developing STARLING, a database management system designed for his website. He was assisted in his work by Murray Gell-Mann. At the time of his death, he was a professor at the Russian State University for the Humanities, a visiting professor at the Santa Fe Institute, and a frequent guest lecturer at Leiden University in the Netherlands, where he was awarded the degree of doctor honoris causa in June 2005.
Starostin died of a heart attack on September 30, 2005, in Moscow after a lecture at the Russian State University for the Humanities. His son, Georgiy Starostin, is also a linguist.