Athabaskan south

Apache and Navajo speak Southern Athabaskan (Dene) languages related to ones still spoken in interior Alaska and northwestern Canada. Their ancestors migrated south ~1000–1400 CE, likely along the eastern flank of the Rockies or through the Great Basin, arriving in the Southwest not long before the Spanish. They come from the second, later Siberian-related stream rather than the founding dispersal, which is why Na-Dene populations cluster apart from most other Indigenous American groups in genome studies.

The one deep linguistic link that has real traction goes the other direction entirely: Dene-Yeniseian, connecting Athabaskan to the Yeniseian languages of central Siberia. Other non-first-wave groups that fought hard on contact include the Tlingit (destroyed the Russian post at Sitka in 1802), Tsilhqot'in in interior BC, the Rogue River Athabaskans of Oregon, Hupa, Tsuu T'ina with the Blackfoot, and the Plains Apache with the Kiowa.