The language is known primarily from one document, a letter written in 1688 to Charles II of Spain. Geoffrey Kimball has produced a grammatical sketch[3] and a vocabulary of the language[4] based on the contents of the letter.
^Broadwell, George A. (1992). Reconstructing Proto-Muskogean Language and Prehistory: Preliminary results. 3, en. 2. CiteSeerX10.1.1.72.4700.
^Haas, Mary R. (April 1949). "The Position of Apalachee in the Muskogean Family". International Journal of American Linguistics. 15 (2). University of Chicago Press: 121–127. doi:10.1086/464031.
^Kimball, Geoffrey (April 1987). "A Grammatical Sketch of Apalachee". International Journal of American Linguistics. 53 (2). University of Chicago Press: 136–174. doi:10.1086/466050. JSTOR1265142.
^Kimball, Geoffrey (October 1988). "An Apalachee Vocabulary". International Journal of American Linguistics. 54 (4). University of Chicago Press: 387–398. doi:10.1086/466093. JSTOR1265100.