Havasupai is a dialect of the Upland Yuman language spoken by fewer than 450 people on the Havasupai Indian Reservation at the bottom of the Grand Canyon

Grand Canyon

The Grand Canyon is a steep-sided canyon carved by the Colorado River in the United States in the state of Arizona. It is largely contained within the Grand Canyon National Park, the 15th national park in the United States...

. It is the only Native American language in the United States of America spoken by 100% of its indigenous population.

The Havasupai dialect is nearly identical to the dialect of the Hualapai

Hualapai

The Hualapai or Walapai are a tribe of Native Americans who live in the mountains of northwestern Arizona, United States. The name is derived from "hwa:l," the Hualapai word for ponderosa pine, "Hualapai" meaning "people of the ponderosa pine"...

, although the two groups are socially and politically distinct (Kendall 1983:5).