The Tequistlatecan languages are part the proposed Hokan family, but are often considered to be distinct family. Campbell and Oltrogge (1980) proposed that the Tequistlatecan languages may be related to Jicaquean (see Tolatecan), but this hypothesis has not been generally accepted.
Campbell, Lyle and Oltrogge, David. 1980. Proto-Tol (Jicaque). International Journal of American Linguistics, 46:205-223
Campbell, Lyle. 1979. "Middle American languages." In L. Campbell & M. Mithun (Eds.), The Languages of Native America: Historical and Comparative Assessment, (pp. 902–1000). Austin: University of Texas Press.
Campbell, Lyle. 1997. "American Indian Languages, The Historical Linguistics of Native America." In Oxford Studies in Anthropological Linguistics. Oxford: Oxford University Press