Conversation so far:
when did the navajo arrive in the southwest
Anthropologists hypothesize that the Navajo split off from the Southern Athabaskans and migrated into the Southwest between 200 and 1300 A.D.
where did the navajo migrate to in the southwest
Between 900 and 1525 A.D. the Navajos developed a rich and complex culture in the area of present-day northwestern New Mexico.

Question: what language did the people speak
Self-contained rewrite: what language did the navajo speak