The so-called "Plateau tribes" did not all speak the same language:
Although many of these languages are related they are not always mutually understandable; Yakima Shahaptin is not the same as Nez Perce Shahaptin for example.
Algonqulan Or Algonkian
The Inuit are not Indians and the Inuit have many different languages. It's like asking someone what did Europeans speak?
The Lenape spoke Lenape Languagealso known as Unami.
they have fun!
river
The tribes that speak Salishan languages may be conveniently divided into Northern Plateau and Interior Salish; there are also Coast Salish among the Northwest Coast Indians. The Northern Plateau Salish include the Shuswap, Lillooet, and Ntlakapamux
The Manhasset indians spoke the Munsee and Unami languages.
Algonquian!
Caddoan
Sourashtian
Sioux
english.
algonquon
english.
Algonqulan Or Algonkian
They spoke Caddoan
Iroquian and/or Ojibway