How do the Unangan differ from the Sugpiaq or Alutiiq people in language ancestry?

The Unangan and the Sugpiaq (or Alutiiq) people differ significantly in their linguistic ancestry, a distinction often obscured by historical colonial terminology.

The Eskimo-Aleut language family is divided into two primary branches: Aleut and Eskimo.1

• Unangan: These people are the speakers of Unangam Tunuu, which constitutes the entire Aleut branch of the language family. They are indigenous to the Aleutian Islands and the western tip of the Alaska Peninsula.1234
• Sugpiaq/Alutiiq: These groups belong to the Eskimo branch, specifically the Yupik division. They speak Pacific Yupik—also known as Sugcestun, Sugpiaq, or Alutiiq—and are native to areas such as Kodiak Island and Prince William Sound.154

Confusion between these groups arose because Russian colonizers applied the term "Aleut" to both the Unangan and the culturally distinct Sugpiaq/Alutiiq peoples. While the names "Alutiiq" and "Sugpiat" are sometimes used by the latter groups, they remain linguistically distinct from the Unangan, who are the only group descended from speakers of the Unangam Tunuu language.64