Navajo language
She returned to work with Navajo during the middle 1930s and continued until the early 1950s. She started a Navajo school in which she worked with students to develop a practical orthography for the Navajo language. During the 1940s, she undertook a broader analysis of Navajo language, belief system, and religious practice which culminated in the two volume study, "Navaho Religion," published in 1950 by the Bollingen Foundation. An extensive collection of her notes on Navajo ethnology and language is held by the Museum of Northern Arizona.