The library has 10 volumes of grammars, vocabularies, sermons, and other religious writings in the Kaqchikel and K'iche' languages of Guatemala. Several have been studied, notably by Daniel G. Brinton in APS Proceedings 21 (1884): 345, and Nora B. Thompson, "Algunos manuscritos guatemaltecos en Filadelfia", Anales de la Sociedad de Geografia e Historia 23 (1948), Nos. 1 2: p. 3; and all have been described by John F. Freeman, "Manuscript Sources on Latin American Indians," APS Proceedings 10 (1962): 530, and in Freeman's Guide to Manuscripts relating to the American Indian (1966).

The Daythal L. Kendall papers consist of a wide variety of published and unpublished work on especially Takelma, Kalapuyan languages, and Lencan languages. A linguist and computer scientist, Kendall devoted much time to synchronic and diachronic linguistics of Takelma and the Penutian stock, including much research on Takelma poetic forms, Kalapuyan morphology and gathering a large unpublished lexicon for Lencan languages. He also produced pedagogical materials for learning Canadian Aboriginal syllabics, and worked twice for the American Philosophical Society to develop their understanding of their Native American collections. In the papers are correspondence, extensive research and manuscripts on the above, collected materials from others including many handouts from conferences (particularly the Society for the Study of the Indigenous Languages of the Americas), lexical slips, and photographs of Native Oregonians and their land.