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.
[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: 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').