Silent articulation modulates auditory and audiovisual speech perception.

The concept of an internal forward model that internally simulates the sensory consequences of an action is a central idea in speech motor control. Consistent with this hypothesis, silent articulation has been shown to modulate activity of the auditory cortex and to improve the auditory identification of concordant speech sounds, when embedded in white noise. In the present study, we replicated and extended this behavioral finding by showing that silently articulating a syllable in synchrony with the presentation of a concordant auditory and/or visually ambiguous speech stimulus improves its identification. Our results further demonstrate that, even in the case of perfect perceptual identification, concurrent mouthing of a syllable speeds up the perceptual processing of a concordant speech stimulus. These results reflect multisensory-motor interactions during speech perception and provide new behavioral arguments for internally generated sensory predictions during silent speech production.