Title
Phonetic modification of vowel space in storybook speech to infants up to 2 years of age
Document Type
Article
Publication Date
January 2015
Publication Title
Journal of Speech, Language, and Hearing Research
First Page
241
Last Page
253
DOI
https://dx.doi.org/10.1044%2F2015_JSLHR-S-13-0205
Abstract
Purpose: A large body of literature has indicated vowel space area expansion in infant-directed (ID) speech compared with adult-directed (AD) speech, which may promote language acquisition. The current study tested whether this expansion occurs in storybook speech read to infants at various points during their first 2 years of life. Method: In 2 studies, mothers read a storybook containing target vowels in ID and AD speech conditions. Study 1 was longitudinal, with 11 mothers recorded when their infants were 3, 6, and 9 months old. Study 2 was cross-sectional, with 48 mothers recorded when their infants were 3, 9, 13, or 20 months old (n = 12 per group). The 1st and 2nd formants of vowels /i/, /ɑ/, and /u/ were measured, and vowel space area and dispersion were calculated. Results: Across both studies, 1st and/or 2nd formant frequencies shifted systematically for /i/ and /u/ vowels in ID compared with AD speech. No difference in vowel space area or dispersion was found. Conclusions: The results suggest that a variety of communication and situational factors may affect phonetic modifications in ID speech, but that vowel space characteristics in speech to infants stay consistent across the first 2 years of life.
Recommended Citation
Burnham, E. B., Wieland, E. A., Kondaurova, M V., McAuley, J. D., Bergeson, T. R., Dilley, L. C. (2015). Phonetic modification of vowel space in storybook speech to infants up to 2 years of age. Journal of Speech, Language, and Hearing Research, 58, 241-253.
