Proto-Eskimo–Aleut was the common ancestor of the Eskimo languages and Aleut. Its existence is known through similarities in Eskimo and Aleut. The existence of Proto-Eskimo–Aleut is generally accepted among linguists. It was for a long time true that no linguistic reconstruction of Proto-Eskimo–Aleut had yet been produced, as stated by Bomhard (2008:209). Such a reconstruction was offered by Knut Bergsland in 1986. Michael Fortescue (1998:124-125) has offered another version of this system, largely based on the reconstruction of Proto-Eskimo in the Comparative Eskimo Dictionary he co-authored with Steven Jacobson and Lawrence Kaplan (1994:xi).
There are no generally accepted relations between Proto-Eskimo–Aleut and other language families. A substantial case for a genetic relationship between Proto-Eskimo–Aleut and several languages of northern Eurasia was published by Michael Fortescue in 1998 in Language Relations across Bering Strait (see Uralo-Siberian languages).
Bergsland, Knut. 1986. "Comparative Eskimo–Aleut phonology and lexicon." Journal de la Société finno-ougrienne 80:63-137.
Bomhard, Allan R. 2008. Reconstructing Proto-Nostratic: Comparative Phonology, Morphology, and Vocabulary, 2 volumes. Leiden: Brill.
Fortescue, Michael, Steven Jacobson, and Lawrence Kaplan. 1994. Comparative Eskimo Dictionary with Aleut Cognates. Alaska Native Language Center.
Fortescue, Michael. 1998. Language Relations across Bering Strait: Reappraising the Archaeological and Linguistic Evidence. London and New York: Cassell.