Early theories of speech perception

Early theories of speech perception incorporated knowledge of speech production. The Motor Theory held that innate knowledge of speech gestures mediated the auditory perception of speech, even in infants (27). Analysis by Synthesis incorporated listeners ’ motor knowledge in speech perception as a “ prior, ” and argued that speech production experience enabled listeners to generate internal motor models of speech that served as hypotheses to be tested against incoming sensory data (30).Early models of developmental speech perception, such as our Native Language Neural Commitment concept (1), described a process of “ neural commitment ” to the auditory patterns of native speech. Revisions in the model, named Native Language Magnet-Expanded (NLM-e), described emergent links between speech perception and production (9). The present data will allow further refinement of the model by suggesting how speech perception and speech production become linked early in development: infants ’ brains respond to hearing speech by activating motor brain areas, coregistering perceptual experience and motor brain patterns. Given 20-wk-old infants ’ abilities to imitate vowels in laboratory tests by generating vocalizations that acoustically and perceptually correspond to the ones they hear(74), we posit that infants use prior speech production experience to generate internal motor models of speech as they listen to us talk.To our knowledge, the present data suggest, for the first time,a developmental theory that refines previous theory by incorporating infants ’ nascent speech production skills in speech perception learning. On this view, both auditory and motor components contribute to the developmental transition in speech perception that occurs at the end of the first year of life.