How are the Eskimo and Aleut branches related within the Eskimo-Aleut language family?

The Eskimo-Aleut language family is internally divided into two primary branches: Eskimo and Aleut. While these branches are related as part of the same language stock, they are distinct in their linguistic development and structure.12

The relationship between the two is evidenced by shared linguistic features, such as the use of certain consonants articulated with the tongue, including the uvular q. However, they also exhibit significant differences; for instance, while Eskimo languages typically use only a single consonant in the initial position, Unangam Tunuu (the Aleut language) features initial consonant clusters resulting from historical vowel loss. Furthermore, specific sounds in Unangam Tunuu correspond to cognates in Eskimo languages, demonstrating their common ancestry despite these phonological divergences.3

The Eskimo branch is further subdivided into the Inuit and Yupik divisions, whereas the Aleut branch currently consists of a single language, Unangam Tunuu, which possesses two surviving dialects. Although various theories have been proposed to link this family to other groups, such as Uralic or Chukotko-Kamchatkan, these relationships remain conjectural, and the family is generally considered an isolated stock.412