Speech Production and Perception

Abstract

One way to investigate speech motor learning is to create artificial adaptation situations by perturbing speakers' auditory feedback in real time. Formant perturbations were introduced by Houde and Jordan (1998), providing the first evidence that speakers adapt their pronunciation to compensate for these perturbations. Twenty years later, this chapter provides an overview of the general impact of Houde and Jordan's work in speech research and beyond, as well as a more detailed review of studies that involve formant perturbations. The impact of Houde and Jordan's work appears to be cross-disciplinary. Although mainly related to speech production and perception, it has also been cited in the limb movement and even animal research, mainly as evidence of adaptive sensorimotor control. Formant perturbations research has expanded rapidly since 2006, spreading across the world and many research teams. We identified 77 experimental studies focused on formant perturbations which we then analyzed with regard to technical and theoretical issues. This analysis showed that various apparatuses and procedures were used to address important topics of speech research. A primary interest has been in feedback and feedforward control mechanisms in speech. These mechanisms were addressed in different populations, including adults and children with typical vs. atypical development, with behavioral or neurophysiological approaches, or both. Some formant perturbations studies more specifically focused on the integration of auditory and somatosensory feedback in speech production, while others explored the interaction between speech production and perception of phonemic contrasts. Some research questioned the processes and the nature of speech representations by investigating generalization of adaptation to formant perturbations. Finally, a few studies were interested in the effect of extraneous variables such as surface effects or speakers' general cognitive abilities. Altogether, these studies provide insights into speech motor control in general and into the understanding of sensorimotor interactions in particular. The field has developed recently and may still expand in the future, as it allows us to address fundamental topics in speech research such as perception-production links or abstract vs. exemplar representations. Future Caudrelier and Rochet-Capellan research with formant perturbations may also further connect sensorimotor adaptation to linguistic and cognitive factors and in particular to working and long-term memory.