Phonetic variation in consonants in infant-directed and adult-directed speech: The case of regressive place assimilation in word-final alveolar stops
Journal of Child Language
Pronunciation variation is under-studied in infant-directed speech, particularly for consonants. Regressive place assimilation involves a word-final alveolar stop taking the place of articulation of a following word-initial consonant. We investigated pronunciation variation in word-final alveolar stop consonants in storybooks read by forty-eight mothers in adult-directed or infant-directed style to infants aged approximately 0;3, 0;9, 1;1, or 1;8. We focused on phonological environments where regressive place assimilation could occur, i.e., when the stop preceded a word-initial labial or velar consonant. Spectrogram, waveform, and perceptual evidence was used to classify tokens into four pronunciation categories: canonical, assimilated, glottalized, or deleted. Results showed a reliable tendency for canonical variants to occur in infant-directed speech more often than in adult-directed speech. However, the otherwise very similar distributions of variants across addressee and age group suggested that infants largely experience statistical distributions of non-canonical consonantal pronunciation variants that mirror those experienced by adults.
Dilley, L., Millett, A., McAuley, J. D., & Bergeson, T. R. (2014). Phonetic variation in consonants in infant-directed and adult-directed speech: The case of regressive place assimilation in word-final alveolar stops. Journal of Child Language, 41(1), 155-175. PMID: 23388188