Control and representations in speech production

Abstract

In this paper the issue of the nature of the representations of the speech production task in the speaker's brain is addressed in a production-perception interaction framework. Since speech is produced to be perceived, it is hypothesized that its production is associated for the speaker with the generation of specific physical characteristics that are for the listeners the objects of speech perception. Hence, in the first part of the paper, four reference theories of speech perception are presented, in order to guide and to constrain the search for possible correlates of the speech production task in the physical space: the Acoustic Invariance Theory, the Adaptive Variability Theory, the Motor Theory and the Direct-Realist Theory. Possible interpretations of these theories in terms of representations of the speech production task are proposed and analyzed. In a second part, a few selected experimental studies are presented, which shed some light on this issue. In the conclusion, on the basis of the joint analysis of theoretical and experimental aspects presented in the paper, it is proposed that representations of the speech production task are multimodal, and that a hierarchy exists among the different modalities, the acoustic modality having the highest level of priority. It is also suggested that these representations are not associated with invariant characteristics, but with regions of the acoustic, orosensory and motor control spaces.

The complementary roles of auditory and motor information evaluated in a Bayesian perceptuo-motor model of speech perception.

“…Accumulating evidence for the role of motor knowledge in speech perception may be combined with accumulating evidence for the role of perceptual representations and processes in speech motor control (see reviews in Guenther, Hampson, & Johnson, 1998; Perrier, 2005). Importantly, the current perceptuo-motor model of speech perception capitalizes on a set of computational bricks traditionally involved in speech production models.…”

“…5VLAM is actually an articulatory rather than a motor model of speech production. VLAM inputs are parameters controlling the shape of the tongue and lips and the position of the jaw, which are themselves the results of motor commands at a higher level (see, e.g., Perrier, 2005; Perrier et al, 1996). We consider as a simplification that VLAM articulatory parameters are part of the control system and hence could provide “motor commands” at a certain level of representation in the motor pathway.…”

“…Notice that the visual system could intervene in this process, especially considering the natural complementarity of auditory and visual representations in the depiction of vowels and plosives(Robert-Ribes et al, 1998;Summerfield, 1987).5 VLAM is actually an articulatory rather than a motor model of speech production. VLAM inputs are parameters controlling the shape of the tongue and lips and the position of the jaw, which are themselves the results of motor commands at a higher level (see, e.g.,Perrier, 2005;Perrier et al, 1996). We consider as a simplification that VLAM articulatory parameters are part of the control system and hence could provide "motor commands" at a certain level of representation in the motor pathway.…”

Face‐to‐Face Communication

“…Thus it is argued that the goal of vocal tract actions should be formulated in the acousticauditory domain (Perkell et al 1997, Guenther et al 1998, or that the goal is multimodal with the acoustic-auditory modality having the highest level of priority (Perrier 2005). The multimodality of speech action goals is also supported by Nasir and Ostry (2008) claiming that speakers have precise somatosensory expectations independent of auditory goals.…”

KLAIR: a virtual infant for spoken language acquisition research

“…But in addition it is important to know where the articulators are currently positioned, particularly in the presence of noise and perturbations, since in these cases feed-forward control will make inadequate predictions. Perrier [11] found evidence that mental representations of speech production are multimodal, associated with regions of the acoustic, orosensory and motor control spaces, with the acoustic modality having the highest level of priority Multimodality also provides additional channels for communication between agent and caregiver. Sensing the caregiver's response to an utterance will be useful to the agent for reinforcement learning and for turn-taking.…”