This study examines the production and perception of laryngeal constriction in the early vocalizations of Bai and English infants. The first part of the study documents the development of laryngeal voice quality features in the non-syllabic and syllabic utterances of Bai and English infants. The second part of the study focuses on the perception of laryngeal constriction in infant vocalizations by adult Bai and English listeners. The study is grounded in Esling’s (2005) model of the vocal tract, which characterizes the laryngeal vocal tract as a separate articulator, distinct from the oral vocal tract.
The study of Bai and English infants’ production identifies universal and language-specific patterns in infants’ development of laryngeal constriction. In the first months of life, most sounds produced by Bai and English infants are constricted. As the year progresses, all infants explore degrees of constriction in dynamic utterances that feature alternations between constricted and unconstricted laryngeal voice quality settings. As well, throughout the year, infants produce an increasing proportion of unconstricted vocalizations. By the end of the first year, when infants have developed increasing control of the laryngeal and oral vocal tracts, they produce syllabic utterances that begin to reflect the use of laryngeal voice quality features in their ambient language. English syllabic utterances are mostly unconstricted, mirroring the prevalence of unconstricted settings in the target language. By contrast, Bai syllabic utterances are mostly constricted or dynamic, reflecting the use of laryngeal voice quality in Bai, a register tone language that employs laryngeal voice quality features distinctively at the syllabic level.
The second part of the study highlights universal and language-particular patterns in Bai and English adults’ perception of laryngeal voice quality in infants’ utterances. In evaluating the importance of a range of infant sounds in learning the target language (Bai or English), adults from both language groups assign lower ratings to infant utterances that occur earlier in development, such as constricted non-syllabic utterances, and higher ratings to sounds that occur later, such as syllabic utterances with rapidly articulated syllables. Bai and English adults’ perceptions also reflect some language-specific patterns that correspond to language-particular characteristics identified in infants’ use of laryngeal voice quality in syllabic and non-syllabic utterances. These correspondences suggest that adults are attuned to laryngeal voice quality in infants, and that, in turn, infants become attuned to the use of laryngeal voice quality features in their ambient language early in development.
The production study demonstrates the fruitfulness of Esling’s (2005) model of the vocal tract in revealing previously undocumented patterns in the development of laryngeal constriction in the first year of life and in highlighting the importance of emergent laryngeal control as a stimulator of phonetic development. The perception study shows that adults whose native languages differ markedly in their use of laryngeal constriction can systematically evaluate laryngeal voice quality features in the full range of non-distress vocalizations produced by infants in the first year of life.
| Identifer | oai:union.ndltd.org:uvic.ca/oai:dspace.library.uvic.ca:1828/1527 |
| Date | 18 August 2009 |
| Creators | Benner, Allison |
| Contributors | Esling, John H. |
| Source Sets | University of Victoria |
| Language | English, English |
| Detected Language | English |
| Type | Thesis |
| Rights | Available to the World Wide Web |
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