Developmental changes in perceptual weighting and organization of speech.

Abstract

Speech perception research and theory historically have focused on the role of discrete spectro-temporal bits of the signal, known as acoustic cues, in phonetic labeling. Following suit, work in development and/or disorders has asked if sensitivity to these cues is diminished in children or disordered populations relative to typical adults. Although outcomes with disordered populations provide a controversial account, clearer is the conclusion that typical children have sufficient sensitivity to these cues from infancy. Yet equally clear is the finding that abilities to recover phonetic structure in one’s first language emerge only gradually over the first decade or so of life, suggesting more may be involved in mature speech perception than has heretofore been considered. This presentation reviews what research has been done on developmental changes in three phenomena that might help explain that protracted period of development for speech perception: (1) weighting strategies for the numerous cues available for separate phonetic decisions, (2) signal structure that is temporally longer and spectrally broader than acoustic cues, termed “global” structure, and (3) perceptual organization of various kinds of signal structure. These findings should prompt innovation moving forward in how investigators examine developmental change in speech perception. [Work supported by NIDCD Grant DC-00633.]