The Triqui languages
Copala Triqui is one of three Triqui languages -- the others are Chicahuaxtla Triqui and Itunyoso Triqui.
Published research on Copala Triqui
Website of Barbara Hollenbach, from SIL. (In Mexican publications she is often referred to as Elena Erickson de Hollenbach.)
Hollenbach, Barbara E. 1976. Tense—negation interplay in Copala Trique. International Journal of American Linguistics 42:126–32.
Hollenbach, Barbara. 1984a. The phonology and morphology of tone and laryngeals in Copala Trique. Ph.D. thesis, University of Arizona.
Hollenbach, Barbara E. 1992. A syntactic sketch of Copala Trique. Pages 173–431 in C. Henry Bradley and Barbara E. Hollenbach, editors. Studies in the syntax of Mixtecan languages, Volume 4. (Summer Institute of Linguistics and the University of Texas at Arlington Publications in Linguistics 111.) Dallas: Summer Institute of Linguistics and the University of Texas at Arlington.