ABSTRACT
Abstract
There is considerable evidence that speech is perceived by a specialized phonetic module in adults. However, it is still very unclear whether young infants show a similar specialization. Understanding developmental changes in the phonetic specificity of speech perception will clarify the theoretical understanding of modularity. This paper reviews research examining the ontogenetic origin and developmental progression of phonetic perception. Although the focus will be on the study of developmental changes in cross-language speech perception, other recent evidence suggesting early phonetic specialization will also be reviewed.
The cross-language research indicates that young infants can discriminate (and also apparently categorize) nearly every speech sound contrast on which they have been tested, including those that do not occur (or are not used contrastively) in their language-learning environment. However, older children and adults often show more difficulty discriminating nonnative contrasts, particularly those which are assimilated to a single phoneme in their native language.
Research has shown that this developmental change is evident by the end of the first year of life, suggesting that some important reorganization has occurred by this time. The implications of initial phonetically relevant perception to theoretical models of speech perception will be discussed. As well, several alternative explanations for why the developmental reorganization begins to occur around one year of age will be outlined, and new data assessing one of these possibilities will be presented.
