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Phonological and Phonetic Realizations of Downstepping in Child Speech

Recent research has applied an autosegmental-metrical approach to child speech in Dutch, Portuguese, Spanish, and Catalan, and there is an ongoing need to determine how this model and the ToBI transcription system can be used to represent the speech of young children. Specifically, the role of downstepping in child speech has not yet been analyzed in detail. The motivation for this study is to examine the phonetic implementation of the downstepped H+!H* pitch accent, as well as begin to create an inventory of the intonational patterns found in American English-speaking toddlers. Phonological and phonetic analyses were carried out for utterances from two corpora of spontaneous child speech, elicited during a storybook task and a game-based interaction. Phonological results show that H* and H+!H* are the most frequently occurring pitch accents, with other types appearing less frequently (L*, L+H*, L*+H). Phonetic analyses of H+!H* tokens show that its phonetic implementation is varied, with at least six sub types identified when produced with a low boundary tone. Taken together, the results begin to form a picture of the sophisticated intonational patterns present in the speech of young children. Further research is necessary to determine the connection between the phonological and phonetic representations.