From the introduction: "This paper focuses on the fortis/lenis contrast in consonants in the Guichicovi dialect of Mixe (Mixe-Zoquean; Oaxaca, Mexico), and uses instrumental data to support a proposed phonological analysis of this contrast. In the remainder of Sect. 1, I briefly survey prior work on this contrast, especially as it impacts on the claim that Mixe has three contrastive vowel lengths. I summarize the phonetic and phonological facts that were determined by ordinary techniques of phonetic transcription, and describe the phonological hypothesis for which I wanted confirmation from instrumental data. In Sect. 2, I describe the instrumental study, including the words tested, the recording procedures, and the measurements made. In Sect. 3, I present the results of this study. In Sect. 4, I discuss the implications of these results for Mixe and for phonological theory, and present some considerations for the design of a larger, more complete study."
Bickford, J. Albert
"Fortis/lenis consonants in Guichicovi Mixe: A preliminary acoustic study,"
Work Papers of the Summer Institute of Linguistics, University of North Dakota Session: Vol. 29, Article 1.
Available at: https://commons.und.edu/sil-work-papers/vol29/iss1/1