"Eskimo is used to refer to people who inhabit the circumpolar region (excluding Scandinavia and most of Russia, but including the easternmost portions of Siberia). There are two main groups of Eskimos: the Inuit (in northern Alaska, Canada and Greenland) and the Yupik (of western Alaska and the Russian Far East).

The Eskimos are related to the Aleuts and the Alutiiq from the Aleutian Islands in Alaska as well as the Sug'piak from the Kodiak Islands and as far as the Prince William Sound in southcentral Alaska.

Eastern Eskimo people - the Inuit - speak Inuktitut, and western Alaskan Eskimo communities - the Yup'ik - speak Yup'ik. There is something of a dialect continuum between the two, and the westernmost dialects of Inuktitut could be viewed as forms of Yup'ik. Kinship culture also differs between east and west, as eastern Inuit lived with cousins of both parents, but western Inuit lived in paternal kinship groups."
 
Taken directly from Wikipedia
 

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