| 研究実績の概要 |
We investigated the interplay between laryngeal mechanisms, using cross-linguistic acoustic, electroglottographic (EEG), and perceptual data.
Our most important achievement is the phonetic description of the voicing contrast of plosives in Tokyo Japanese. We showed that closure voicing is variably produced in word-initial position but maintained in word-medial position. Crucially, fundamental frequency (F0) of the following vowel contributes largely to the distinction between the two plosive series in word-initial position. These results were compared with languages that are undergoing a similar development.
We then examined the perception of the voicing contrast in Japanese by native and nonnative listeners. We conducted experiments using synthesized stimuli, with Japanese- and French-speaking listeners. Our results showed that closure voicing is the primary cue for both listener groups, but the sensitivity to F0 is stronger with Japanese than French listeners.
Seoul Korean is more advanced in this F0 development, and previous studies also reported a role of voice quality. We recorded EEG data with Korean speakers and found highly variable realization of the voice quality. The only consistency is that vowel is breathier after aspirated and lenis than after fortis plosives.
Altogether, we have demonstrated that while some automatic mechanisms explain the interplay between laryngeal behaviors, the production and perception of the laryngeal contrast depend on individual variability as well as language-specific factors, such as phonological structure and prosodic contexts.
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