Variability revisited: An acoustic, aerodynamic, and respiratory kinematic comparison of children and adults during speech

A review of the kinematic and acoustic literature fails to provideunequivocal support for the general assumption that the child's speech mechanism is more variable than the adult's. The current study, applying a variety of coordinated acoustic and kinematic measures to children and adults ranging from 4 to 30 years, confirms that children are not consistently more variable. In particular, only the four-year-olds show some tendency to produce acoustic, aerodynamic, and respiratory kinematic speech events with more variability than adults. In some instances, adults displayed more variable speech behaviors than children. The author questions both the general assumption of linear development, and the "analytic components" approach to physiological modeling, suggesting rather that development may be multimodal, with different parts of the system developing at different rates at different times, and that a construction-theoretic approach to modeling may be useful.