Rôles de la hauteur et du timbre des voix dans l’organisation perceptive de la parole

Abstract

In this paper, we review the mechanisms involved in fundamental frequency-based grouping and vocal tract length-based grouping of speech segments and continuous speech. Concurrent speech message processing requires a perceptual organisation of the signals rising from each incoming source. This perceptual organisation is based on two kinds of primitive grouping mechanisms: simultaneous grouping (integrating different components of the spectrum occurring at the same time) and sequential grouping (grouping different components of the spectrum over time). For speech, the separation of two concurrent messages is enabled by simultaneous grouping while tracking a message over time is permitted by sequential grouping. Past studies show that the pitch of a voice, mainly determined by fundamental frequency, is an important cue in the simultaneous and sequential grouping of speech. The spectral timbre of a voice, largely fixed by the vocal tract length (determining the spectral envelope of a speech signal), has also a great impact on sequential grouping. Recent studies suggest that the conjunction of fundamental frequency and vocal tract length has a super-additive effect on sequential grouping but not on simultaneous grouping. The effect of dichotic hearing on speech perceptual grouping is discussed in the last part of this paper.