Testing an acoustic model of the P-center in English and Japanese.

The notion of the "perceptual center" or the "P-center" has been put forward to account for the repeated finding that acoustic and perceived syllable onsets do not necessarily coincide, at least in the perception of simple monosyllables or disyllables. The magnitude of the discrepancy between acoustics and perception-the location of the P-center in the speech signal- has proven difficult to estimate, though acoustic models of the effect do exist. The present study asks if the P-center effect can be documented in natural connected speech of English and Japanese and examines if an acoustic model that defines the P-center as the moment of the fastest energy change in a syllabic amplitude envelope adequately reflects the P-center in the two languages. A sensorimotor synchronization paradigm was deployed to address the research questions. The results provide evidence for the existence of the P-center effect in speech of both languages while the acoustic P-center model is found to be less applicable to Japanese. Sensorimotor synchronization patterns further suggest that the P-center may reflect perceptual anticipation of a vowel onset.

Preboundary lengthening in Japanese: To what extent do lexical pitch accent and moraic structure matter?

In this acoustic study, preboundary lengthening (PBL) in Japanese is investigated in relation to the prosodic structure in disyllabic words with different moraic and pitch accent distributions. Results showed gradient progressive PBL effects largely independent of the mora count. The domain of PBL is better explained by the syllable structure than the moraic structure. PBL, however, is attracted toward a non-final moraic nasal, showing some role of the mora. The initial pitch accent does not attract PBL directly, but it suppresses PBL of the final rime as a way of maintaining the relative prominence, showing a language-specific PBL modulation.