Tilquiapan Zapotec (Zapoteco de San Miguel Tilquiápam) is an Oto-Manguean language of the Zapotecan branch, spoken in southern Oaxaca, Mexico.
Santa Inés Yatzechi Zapotec is close enough to be considered a dialect, and Ocotlán Zapotec is also close. They were measured at 87% and 59% intelligibility, respectively, in recorded text testing.[2]
Each vowel can also be glottalized, a phenomenon manifested as either creaky voice throughout the vowel or, more commonly, as a sequence of a vowel and a glottal stop optionally followed by an echo of the vowel.[4]
As with other Zapotec languages, the primary distinction between consonant pairs like /t/ and /d/ is not of voicing but between fortis and lenis (measured in length[6]), respectively, with voicing being a phonetic correlate.[5] There are two exceptions to this in Tilquiapan:
The contrast between fortis /nː/ and lenis /n/
The contrast between fortis /ld/ and lenis /l/
Neither is voiceless, but /nˑ/ is pronounced a little longer and /ld/ replaces /l/ in certain causative verbs in ways similar to other fortis/lenis consonantal changes (e.g. [blaˀa] 'get loose' vs. [bldaˀa] 'let loose').[5]
Nellis, Donald G.; Hollenbach, Barbara E. (1980), "Fortis versus lenis in Cajonos Zapotec phonology", International Journal of American Linguistics, 46 (2): 92–105, doi:10.1086/465639, S2CID144452370