Legislation
The following is a collection of relevant legislation that has affected not only the Navajo but almost all other indigenous peoples. The latter half consists of legislation targeted at supporting the revitalization and support of native languages.
The Native American Programs Act (NAPA) was passed in 1974 and provides financial resources/support to Native peoples whether or not they are federally recognized or not.
Esther Martinez Native American Languages Preservation Act
Esther Martinez is one of the greatest advocates for restoring native languages. In 2006, Congress passed an act that dedicated a significant amount of funding for native language development and/or restoration. The page linked above is the reauthorization of funding through 2024.