Voiceless nasal consonants are typologically rare in the world’s languages. The present study investigates the acoustic realization of reported voiceless nasals in the Miyako Ryukyuan dialect Ikema. Voiceless nasals in Ikema occur word-initially and word-medially as part of a geminate or consonant cluster, and are phonemically distinct from modal voiced nasals. Initial observation of collected recordings revealed many instances of the voiceless phoneme with voicing throughout, leading to a re-evaluation of previous claims about its phonetic implementation. We hypothesized that word-medial and phrase-medial voiceless nasals surface as breathy voiced nasals. We analyzed the acoustic characteristics of nasal components of target words, focusing on duration, phonation state, and cepstral peak prominence (CPP), to determine whether reported voiceless nasal phonetic components with voicing are acoustically distinct from modal voiced nasal consonants. We find that voiceless nasals are produced with a voiceless component followed by a modal voiced component. Voiceless components and breathy components are found to be significantly shorter than modal components. We also find a significant difference between modal nasal, breathy nasal and voiceless nasal components’ CPP values. The results confirm the observation that Ikema voiceless nasals are phonemically distinct from modal nasal consonants, and likely allophonically vary with breathy voiced nasals word-medially and phrase-medially. These findings align with the hypothesis that voiceless nasals require some voicing to be audible for perception, and are consistent with cross-linguistic findings, contributing to the typological understanding of the acoustics of voiceless nasals.

Ford, C., Tucker, B. V., & Ono, T. (2022). Voiceless nasals in the Ikema dialect of Miyako Ryukyuan. Journal of the International Phonetic Association, 1–18.