On the development of speech perception and production: Evidence from the vowel duration cue to final consonant voicing.

A major problem in explaining the relationship between speech perception and speech production has been the lack of comparable measures. The major purposes of the present study were to assess: (1) the development of the perception, production, and perception/production relationships in children for the vowel duration cue to final consonant voicing by comparing analogous measures of category boundary, category separation, and variability in perception and production and (2) the development of discrimination in relation to the categorical and dual coding models of speech perception. The major findings and conclusions were: (1) correlations between analogous perception and production measures of category boundary, category separation, and variability were low and non-significant and appear to support a model in which perception and production are distinct mechanisms; (2) the findings that production ability develops through 10-11 years of age, perception ability becomes adult-like by 7-8 years of age, and perceptual development is more advanced than production development are consistent with the explanation that both perception and production gradually develop over a number of years with perception preceding production; (3) the consistent finding that perceptual variability is more adult-like than production variability implies that the stabilizing of perceptual categories may contribute to the stabilizing of production categories. Neuromuscular maturation also appears to be operating, since production variability is not adult-like until after 10-11 years of age even though perceptual variability is adult-like by 7-8 years of age; and (4) the generally better success in predicting observed discrimination by the dual coding model of speech perception than the phonetic model implies that subjects are relying on auditory information more than articulatory information in making discrimination judgments.Ph.D.Speech therapyDevelopmental psychologyUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/161828/1/8812935.pd