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Highland Chinantec is a Chinantecan language of Mexico, spoken in Comaltepec, San Juan Quiotepec, and surrounding towns in northern Oaxaca. It has a complex system of tone and vowel length compared to other Chinantec languages. The two principal varieties, Quiotepec and Comaltepec, have marginal mutual intelligibility. Yolox Chinantec is somewhat less divergent.
Anderson, Judi Lynn, Martínez, Isaac H., & Pace, Wanda. (1990). Comaltepec Chinantec Tone. In William R. Merrifield & Calvin R. Rensch (Eds.), Syllables, Tone, and Verb Paradigms: Studies in Chinantec Languages 4 (pp. 3-20). Dallas, TX: Summer Institute of Linguistics.
Silverman, Daniel. (1997). Tone Sandhi in Comaltepec Chinantec. Language, 73(3), 473-492.
Robbins, Frank E. (1961). Quiotepec Chinantec Syllable Patterning. International Journal of American Linguistics, 27(3), 237-250.