Refinement of speech motor control in preschool-aged speakers.

Abstract

This investigation explored whether meaningful subgroups of children would emerge from a heterogeneous population of typical preschool speakers as a result of convergences of measures from multiple speech production subsystems: behavioral, phonatory, articulatory, and respiratory. Because variability is a ubiquitous characteristic of preschool speech production, the goal of this classification was not only to minimize within-subgroup variability, but to identify the latent parameters across speech subsystems that characterized each resulting subgroup with the goal of better understanding the refinement of speech motor control that takes place at this stage of development. It is critical to understand the range of performance and interactions among speech production subsystems that exist in children with typical speech development so that we can better quantify the deviancies observed in children with speech disorders. Data were gathered from 60 speakers, aged 37–59 months, and analyzed using multivariate pattern-based classification analyses. The result was two distinct clusters of individuals whose performance across speech subsystems was differentiated by stability. One group was characterized by higher levels of variability across phonatory, articulatory, and respiratory subsystems compared to the second group. The groups did not differ significantly by composition in terms of age or sex.