The Eskimo–Aleut language family is divided into two branches: the Eskimo languages and the Aleut language. The Aleut branch consists of a single language, Aleut, spoken in the Aleutian Islands and the Pribilof Islands. It is divided into several dialects. The Eskimo languages are divided into two branches: the Yupik languages, spoken in western and southwestern Alaska and in easternmost Siberia, and the Inuit languages, spoken in northern Alaska, Canada and Greenland. Inuit, which covers a huge range of territory, is divided into several varieties. Neighbouring varieties are quite similar, although those at the farthest distances from the centre in the Diomede Islands and East Greenland are quite divergent.
The proper place of one language, Sirenik, within the Eskimo family has not been settled. While some linguists list it as a branch of Yupik, others list it as a separate branch of the Eskimo family, alongside Yupik and Inuit.
The Alaska Native Language Center believes that the common ancestral language of the Eskimo languages and of Aleut divided into the Eskimo and Aleut branches at least 4,000 years ago. The Eskimo language family split into the Yupik and Inuit branches around 1,000 years ago.
The Eskimo–Aleut languages are among the native languages of the Americas. This is a geographical category, not a genealogical one. The Eskimo–Aleut languages are not demonstrably related to the other language families of North America and are believed to represent a separate, and the last, prehistoric migration of people from Asia.
Alexander Vovin (2015) notes that Northern Tungusic languages, which are spoken in eastern Siberia and northeastern China, have Eskimo-Aleut loanwords that are not found in Southern Tungusic, implying that Eskimo-Aleut was once much more widely spoken in eastern Siberia. Vovin (2015) estimates that the Eskimo-Aleut loanwords in Northern Tungusic had been borrowed no more than 2,000 years ago, which was when Tungusic was spreading up north from its homeland in the middle reaches of the Amur River. Vovin (2015) considers the homeland (Urheimat) of Proto-Eskimo-Aleut to be in Siberia rather than in Alaska.
Eskimo–Aleut does not have any genetic relationship to any of the world's other language families that is generally accepted by linguists at the present time. There is general agreement that it is not closely related to the other language families of North America. The more credible proposals on the external relations of Eskimo–Aleut all concern one or more of the language families of northern Eurasia, such as Chukotko-Kamchatkan just across the Bering Strait. One of the first such proposals was made by the pioneering Danish linguist Rasmus Rask in 1818, upon noticing similarities between Greenlandic and Finnish. Perhaps the most fully developed such proposal to date is Michael Fortescue's Uralo-Siberian hypothesis, published in 1998.
More recently Joseph Greenberg (2000–2002) suggested grouping Eskimo–Aleut with all of the language families of northern Eurasia (Indo-European, Uralic, Altaic, Korean, Japanese, Ainu, Nivkh/Gilayak, and Chukchi-Kamchatkan), with the exception of Yeniseian, in a proposed language family called Eurasiatic. Such proposals are not generally accepted. Criticisms have been made stating that Greenberg's hypothesis is ahistorical, meaning that it lacks and sacrifices known historical elements of language in favour of external similarities. Although the Eurasiatic hypothesis is generally disregarded by linguists, one critique by Stefan Georg and Alexander Vovin, stated that they were not willing to disregard the theory immediately, although ultimately agreed that Greenberg's conclusion was dubious. Greenberg explicitly states that his developments were based on the previous macro-comparative work done by Vladislav Illich-Svitych and Bombard and Kerns. By providing evidence of lexical comparison, Greenberg hoped that it would strengthen his hypothesis.