The Navajo and Apache move south

Navajo and Apache speak Athabaskan languages, a family otherwise belonging to northern Canada and Alaska. The linguistic relationship is so clear it could be established before any archaeology existed, and it is among the plainest examples of language tracing a migration. The Navajo later took up sheep herding from the Spanish and weaving from the Pueblo peoples, and made both distinctly their own. In the Second World War, Navajo was used as a code language in the Pacific — a language nobody outside had written down thoroughly enough to break.