Aurelio Espinosa, Sr. was a scholar internationally known for his studies in Spanish and American folklore and philology. Born in El Carnero, Colorado, in the mostly Hispanic San Luis Valley, he learned about Spanish folk tales and ballads from his uncle who lived in the mountains of southern Colorado. He earned his BA and MA at the University of Colorado in Boulder. In between, he became a professor of modern languages at the University of New Mexico. In 1909, he completed his PhD cum laude at the University of Chicago. His dissertation earned him the attention of several people in the United States, one of the most noted being Professor Ford of Harvard University, who recommended him to the head of the Romanic Languages department at Stanford University. Espinosa joined Stanford faculty in 1910 and remained there until his retirement. He was the chairman of the Department of Romanic Languages from 1933 to 1947.

A key figure and often considered a pioneer of Latinx folklore and folklife and Hispanic studies, Professor Espinosa worked collaboratively with Spanish folklorist and ballad scholar Ramón Menéndez and major anthropological folklorists of Native American culture Franz Boas and Elsie Clews Parsons. He combined historical and linguistic investigation with ethnographic documentation of contemporary cultural scenes to build what he envisioned as a scientific field. Along with the study of the interaction between Spanish, English, and Native languages, he also studied Hispanic ballads, folktales, proverbs, riddles, children’s games, and nursery rhymes. He was the first to collect vast numbers of versions of the same ballads/folktales and therefore create a lens into the evolution of New Mexican and Spanish ideas of morality and ethics, human virtue and failing, their political and social views, and their history.

Espinosa was instrumental in establishing the Société Internationale de Dialectologie Romane in 1909, the American Association of Teachers of Spanish in 1917, and the Linguistic Society of America in 1925. He was president of the American Folklore Society (1924–25). He received the Grand Cross of the Order of Alfonso el Sabio (Alfonso the Wise), and was a member of the Instituto de Cultura Hispánica. He was a member of the Royal Spanish Academy, the Hispanic Society of America, and the Academia Hispanoamericana de Ciencias y Letras de Cádiz. Espinosa received two honorary degrees: one from the University of San Francisco, and the other from the University of New Mexico. Among his acclaimed works are:

Romances de Puerto Rico (1918)

Cuentos Populares Españoles, 3 vols. (1926)

Spanish Folk-lore in New Mexico (1926)

The Folklore of Spain in the American Southwest, edited by J. Manuel Espinosa (1990)

Enrique Lamadrid