The Charles E. Fiero Papers contain word lists, texts, illustrations, and audio recordings derived mostly from missionary linguist Fiero's fieldwork among Ojibwe speakers in Ontario, Manitoba, and Minnesota, between the 1950s and the 1990s.

Frank Siebert (1913-1998) is one of the key contributors to the field of Algonquian linguistics. While he did not pursue a degree in linguistics or anthropology, he independently acquired the skills and knowledge of a professional scholar. His work on Penobscot is some of the best and most comprehensive in existence. The Siebert Papers document the interest and work of Frank Siebert in the linguistics of the Algonquian family of languages, particularly Penobscot. The collection includes correspondence, research notes, drafts and published manuscripts by Siebert, as well as secondary sources consulted by Siebert. To a lesser extent, it contains material that documents Siebert's personal life, his interest in book collecting and his career as a physician.

The Jane M. Rosenthal papers contain a wide variety of historical and contemporary audio recordings, texts, elicitations and grammatical descriptions of Nahuatl, particularly the variety spoken in Tlaxcala, Mexico, both from the research of Rosenthal and others. Fieldwork in Tlaxcala (including photographs), archival research in Mexico and Chicago, and the work of many scholars that formed the Friends of Uto-Aztecan are represented.