Development of Velopharyngeal Closure for Vocalization During the First 2 Years of Life Purpose The vocalizations of young infants often sound nasalized, suggesting that the velopharynx is open during the 1st few months of life. Whereas acoustic and perceptual studies seemed to support the idea that the velopharynx closes for vocalization by about 4 months of age, an aeromechanical study contradicted this (Thom, ... Research Article
Research Article  |   March 15, 2018
Development of Velopharyngeal Closure for Vocalization During the First 2 Years of Life
 
Author Affiliations & Notes
  • Kate Bunton
    Department of Speech, Language, and Hearing Sciences, The University of Arizona, Tucson
  • Jeannette D. Hoit
    Department of Speech, Language, and Hearing Sciences, The University of Arizona, Tucson
  • Disclosure: The authors have declared that no competing interests existed at the time of publication.
    Disclosure: The authors have declared that no competing interests existed at the time of publication. ×
  • Correspondence to Kate Bunton: bunton@email.arizona.edu
  • Editor-in-Chief: Julie Liss
    Editor-in-Chief: Julie Liss×
  • Editor: Maria Grigos
    Editor: Maria Grigos×
Article Information
Speech, Voice & Prosody / Speech / Research Articles
Research Article   |   March 15, 2018
Development of Velopharyngeal Closure for Vocalization During the First 2 Years of Life
Journal of Speech, Language, and Hearing Research, March 2018, Vol. 61, 549-560. doi:10.1044/2017_JSLHR-S-17-0208
History: Received May 31, 2017 , Revised October 1, 2017 , Accepted November 21, 2017
 
Journal of Speech, Language, and Hearing Research, March 2018, Vol. 61, 549-560. doi:10.1044/2017_JSLHR-S-17-0208
History: Received May 31, 2017; Revised October 1, 2017; Accepted November 21, 2017

Purpose The vocalizations of young infants often sound nasalized, suggesting that the velopharynx is open during the 1st few months of life. Whereas acoustic and perceptual studies seemed to support the idea that the velopharynx closes for vocalization by about 4 months of age, an aeromechanical study contradicted this (Thom, Hoit, Hixon, & Smith, 2006). Thus, the current large-scale investigation was undertaken to determine when the velopharynx closes for speech production by following infants during their first 2 years of life.

Method This longitudinal study used nasal ram pressure to determine the status of the velopharynx (open or closed) during spontaneous speech production in 92 participants (46 male, 46 female) studied monthly from age 4 to 24 months.

Results The velopharynx was closed during at least 90% of the utterances by 19 months, though there was substantial variability across participants. When considered by sound category, the velopharynx was closed from most to least often during production of oral obstruents, approximants, vowels (only), and glottal obstruents. No sex effects were observed.

Conclusion Velopharyngeal closure for spontaneous speech production can be considered complete by 19 months, but closure occurs earlier for speech sounds with higher oral pressure demands.

Acknowledgments
This work was supported by National Institutes of Health/National Institute on Deafness and Other Communication Disorders R01 DC010140, awarded to Jeannette D. Hoit. The authors want to thank all the graduate students who contributed to this research, especially Caety Chong, Keegan Gallagher, Alyssa Heeman, Sarah (Wikert) Kaskie, Amy Lougher, Amanda (Moody) Morse, Kristin Rumery, Christine (Dawson) Williams, Morgan Wilson, Amanda (Van Vianen) Woodmansee, and Olivia Vinikoor. The authors are grateful to Patricia Jones for her invaluable statistical consultation and analyses and to David Zajac and Mary Alt for their advice on certain aspects of the protocol. Most of all, the authors want to express their gratitude to the late Thomas J. Hixon who was a key player at the inception of this study and who inspired the authors to pursue this line of research.
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