Although much is known about the acoustic characteristics of children's speech, there is comparatively little known about the mechanisms available to a child for producing sounds that can be recognized by listeners as speech, and how those mechanisms may differ from those of an adult system.
The specific aims of the proposed research have been designed to address this gap in knowledge by studying the sound production properties of a child-like speech production system based on a computational modeling approach. The research will be guided by three hypotheses: 1) children develop a sound production system in which the laryngeal sound source interacts nonlinearly with the vocal tract filter to generate harmonic energy;2) children develop the ability to produce vowels and consonants based on the acoustic sensitivity of the vocal tract;and 3) the fundamental frequency of the voice source and the formant frequencies of the vocal tract are tuned by the child speaker to maximize the generation of harmonic energy in a pattern that expresses the acoustic characteristics of the vocal tract in the speech signal. The significance of the project is that it will provide new information about the acoustic, aerodynamic, and kinematic factors that guide speech development. This could lead to new explanations of aspects of children's speech production such as the timing of vocal tract gestures and the coarticulation of speech units. The proposed research may also impact theories of speech production and speech motor control, and facilitate the next generation of speech synthesizers. In turn, the models developed could serve as an empirical framework for testing hypotheses regarding speech impairments in children.

Public Health Relevance

The small size of a child's speech production mechanism generally results in high-pitched speech. The characteristics of these sounds are quite different from the speech produced by adults, even though children can transmit the same clear message to a listener. The long-range goal of this research is to understand how a child develops a vocal sound production system capable of generating intelligible speech at an early age and then continually adapts to the anatomic changes due to growth.

National Institute of Health (NIH)
National Institute on Deafness and Other Communication Disorders (NIDCD)
Research Project (R01)
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Motor Function, Speech and Rehabilitation Study Section (MFSR)
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Shekim, Lana O
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University of Arizona
Schools of Arts and Sciences
United States
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Story, Brad H; Vorperian, Houri K; Bunton, Kate et al. (2018) An age-dependent vocal tract model for males and females based on anatomic measurements. J Acoust Soc Am 143:3079
Story, Brad H; Bunton, Kate (2017) Vowel space density as an indicator of speech performance. J Acoust Soc Am 141:EL458
Story, Brad H; Bunton, Kate (2017) An acoustically-driven vocal tract model for stop consonant production. Speech Commun 87:1-17
Neely, Kimberly D; Bunton, Kate; Story, Brad H (2016) A Modeling Study of the Effects of Vocal Tract Movement Duration and Magnitude on the F2 Trajectory in CV Words. J Speech Lang Hear Res 59:1327-1334
Lester-Smith, Rosemary A; Story, Brad H (2016) The effects of physiological adjustments on the perceptual and acoustical characteristics of vibrato as a model of vocal tremor. J Acoust Soc Am 140:3827
Lester, Rosemary A; Story, Brad H (2015) The effects of physiological adjustments on the perceptual and acoustical characteristics of simulated laryngeal vocal tremor. J Acoust Soc Am 138:953-63
Bunton, Kate (2015) Effects of nasal port area on perception of nasality and measures of nasalance based on computational modeling. Cleft Palate Craniofac J 52:110-4
Story, Brad H; Bunton, Kate (2015) Formant measurement in children's speech based on spectral filtering. Speech Commun 76:93-111
Story, Brad H (2014) Structure, Movement, Sound, and Perception. Perspect Speech Sci Orofac Disord 24:7-20
Story, Brad H (2013) Phrase-level speech simulation with an airway modulation model of speech production. Comput Speech Lang 27:989-1010