SPEECH SOUND ACQUISITION, COARTICULATION, AND RATE EFFECTS IN A NEURAL-NETWORK MODEL OF SPEECH PRODUCTION

This article describes a neural network model of speech motor skill ac quisition and speech production that explains a wide range of data on variability, motor equivalence, coarticulation, and rate effects. Mode l parameters are learned during a babbling phase. To explain how infan ts learn language-specific variability limits, speech sound targets ta ke the form of convex regions, rather than points, in orosensory coord inates; Reducing target size for better accuracy during slower speech leads to differential effects for vowels and consonants, as seen in ex periments previously used as evidence for separate control processes f or the 2 sound types. Anticipatory coarticulation arises when targets are reduced in size on the basis of context; this generalizes the well -known look-ahead model of coarticulation. Computer simulations verify the model's properties.