title: Temporal characteristics of aerodynamic segments in the speech of children and adults.
abstract: OBJECTIVE
  The primary purpose of this study was to determine the temporal characteristics of aerodynamic segments in the normal speech of children and adults without cleft palate. A secondary objective was to determine the within-speaker variability of the segments.
  
  
  METHODS
  Speakers consisted of 46 children aged 6 to 8 years, 41 older children aged 11 to 12 years, and 41 adults aged 18 to 37 years (total n = 128) who repeated the word "hamper" during continuous utterances. The pressure-flow method was used to determine the duration of six segments of the oral air pressure and nasal airflow pulses associated with the /mp/ sequence. Descriptive statistics, including coefficients of variation (COV), were computed for each segment as a function of age and sex of the speakers. Analysis of variance (ANOVA) procedures were used to determine the effects of age, sex, or both on the temporal variables.
  
  
  RESULTS
  ANOVAs indicated statistically significant main effects (p <.008) for age on five of the six temporal measures and for sex on three of the six measures. Five of the six COVs were also statistically significant for age. There were no statistically significant interactions between speaker age and sex for any measure.
  
  
  CONCLUSIONS
  The results indicate distinct patterns of timing for aerodynamic segments of speech produced by children and adults. Overall, adults exhibited less temporal variability than children. The generally longer and more variable segments produced by children suggest diagnostic and treatment implications relative to speakers with velopharyngeal dysfunction.
authors.affiliation: UNC Craniofacial Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA. david_zajac@dentistry.unc.edu
authors.forename: David J
authors.initials: DJ
authors.lastname: Zajac
authors.forename: Alyssa M
authors.initials: AM
authors.lastname: Hackett
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000403:Airway Resistance; D000704:Analysis of Variance; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D010160:Palate, Soft / Q000502:physiology; D010614:Pharynx / Q000502:physiology; D012737:Sex Factors; D013060:Speech / Q000502:physiology*; D013068:Speech Production Measurement; D018709:Statistics, Nonparametric; D013997:Time Factors; D014681:Velopharyngeal Insufficiency / Q000175:diagnosis