Supralaryngeal articulation across voicing and aspiration in Yemba vowels

Both prevoicing and aspiration are thought to affect supraglottal cavity size during and following the production of stop consonants. However, many languages implement stop laryngeal contrasts using both prevoicing and aspiration, making it difficult to independently link observed tongue position differences to one effect or the other. Yemba (Grassfields Bantu) offers a unique opportunity to separately study these two effects, as the language contains stop consonants which independently vary in prevoicing and aspiration. The current study examines tongue position in vowels following Yemba stop consonants using acoustic and ultrasound data. Formant frequencies of vowels following stops suggest that stop prevoicing conditions tongue root advancement and tongue body lowering, resulting in an expansion of the supraglottal cavity; the same data suggest that stop aspiration conditions tongue root retraction, resulting in an opposing contraction of the supraglottal cavity. Ultrasound data for a subset of acoustic study participants was not entirely consistent with the acoustic data, showing tongue body lowering and root retraction after aspirated stops, but no consistent lingual adjustments after prevoiced stops. These findings, from the first phonetic study of a Bamileke language's laryngeal contrasts, lend support to active cavity constriction as a supporting mechanism for aspiration.