The acquisition of English rhythm as a function of changes in phrase-level prosody

Abstract

Language rhythm emerges from a combination of lexical and phrase-level prosody. This talk will review evidence from on-going and completed studies on the acquisition of English prosody in typically developing school-age children to show that the surprisingly protracted acquisition of English rhythm is due to the extended acquisition of phrase-level prosody rather than to immature lexical stress production. Cross-sectional and longitudinal data from 20 native American-English speaking children indicate that whereas adult-like rhythm may not be fully acquired until age 8, even the youngest children have mastered lexical stress. Unlike eight-year-olds, though, younger children show less reduced vowels in function words and a less robust pattern of phrase-final lengthening. We argue, based on evidence from a separate study on stress-shifting in 25 six-year-olds and 25 adults, that younger children have yet to fully integrate lexical patterns into phrase-level prosodic structures. A lack of complete integration between lexical and phrasal levels may account for the extended acquisition of prosodically conditioned vowel reduction, which in turn could account for the prolonged acquisition of English rhythm. [Work supported by NIH Grant R01 HD061458.]