The relation between speech perception and phonemic awareness: evidence from low-SES children and children with chronic OM.

The Developmental Weighting Shift (DWS) suggests that children adjust the weights they assign to the acoustic parameters of the speech signal as they gain experience with a native language, and that this developmental shift in perceptual weighting strategies is related to another developmental change: increased sensitivity to the phonetic structure of the speech signal. To test these claims, children presumed to differ in the amount of linguistic experience they had received during their preschool years participated in two kinds of tasks: a labeling task designed to estimate differences among groups in the weights assigned to various acoustic parameters, and tasks of phonemic awareness. The experimental groups were children from low-socioeconomic (low-SES) backgrounds, children with histories of chronic otitis media (OM), and children who experienced both conditions. A control group of children who experienced neither of these conditions also participated. The hypotheses were that, because of their diminished linguistic experience, children in the three experimental groups would display both more immature weighting strategies and poorer phonemic awareness than children in the control group, and that developmental advance in perceptual weighting strategies and phonemic awareness would be correlated. Results indicated that children with histories of chronic OM performed more poorly on both kinds of tasks than did children in the control group, and low-SES children performed more poorly still. Children experiencing both low-SES and chronic OM performed no differently than the low-SES children. These results provide support for the claim that the development of mature perceptual weighting strategies for speech and of phonemic awareness are related. Support is also provided for the claim that both depend on receiving sufficient and appropriate experience with a native language during the preschool years.