Comanche has six vowel qualities /i, e, a, o, u, ɨ/ (plus a length distinction), and while the literature agrees almost completely on /i, e, a, o, u/, the last vowel /ɨ/ has been problematic—described as central in some papers, back in others, and compared to both round and spread vowels of English. This paper provides an acoustic description of the Comanche vowel system based on recordings of six native speakers which suggests that Comanche /ɨ/ is actually a central mid vowel—not a high vowel. The discrepancy with the literature is attributed to three factors: a lack of prior acoustic research on Comanche, perceptual interference from the English language, and the prevalence of /ɨ/ in the literature on Numic languages. If other related languages turn out to require the reclassification of /ɨ/ as a mid vowel, this could have implications for the reconstruction of the Uto-Aztecan vowel system.