Voice onset time of children with functional articulation disorders

Objectives: Various factors associated with the speech motor control skills in children with functional articulation disorders (FAD) have been studied. Voice onset time (VOT) is a temporal acoustic parameter that reflects motor speech coordination skills. In this study, we investigated the VOT of the VCV syllables which contain plosives classified according to the place of articulation and phonation types for children with FAD in comparison with children with typical speech development (TSD). Methods: Fifteen children with FAD were included in this study, ranging from 3 years and 11 months to 8 years and 11 months. Fifteen children with TSD as a control group were matched to the children with FAD on the basis of chronological age within ±3 months. All children produced plosives in isolation and VOTs were measured by the CSL program. A three-way mixed design was used with the groups as a between-subject factor, the place of articulation and phonation types as within-subject factors. Results: There were not significant differences in VOTs between children with FAD and children with TSD. There were significant differences in VOT among the place of articulation, showing that children had the longest VOT for velars (all p<.001). In addition, the VOTs for aspirated consonants were longer than other consonants, and the differences were significant among three phonation types (all p<.001). Conclusion: The current results suggested that children with FAD can control the speech timing between the structures of the larynx and the oral cavity at the same levels of children with TSD.