Measurable acoustic variants as predictors of progress in speech therapy

Abstract

Despite the availability of free, user-friendly acoustic analysis programs, acoustic documentation of speech sound change during speech therapy is rarely mentioned in speech research literature. Thus, the utility of acoustic analysis to document speech change over time in children with speech errors is unknown. A prior study documented children’s /s/ productions as they progressed through speech therapy and compared spectrographic analysis of productions to clinicians’ perceptual judgments of accuracy. Results indicated a greater number of /s/ productions were judged accurate based on visual (acoustic) analysis vs auditory (perceptual) judgment for all clients, particularly during a period of time when clients’ /s/ productions were becoming more frequently accurate. The purpose of this current investigation is to identify the measurable acoustic features of /s/ production that indicate when an individual’s /s/ production is improving even when the productions are still heard as incorrect. By comparing productions identified as correct visually but incorrect auditorily to productions identified the same both visually and auditorily, this study identifies acoustic variants that are indicative of subtle improvements in production not yet identifiable by adult listeners. These subtle, yet measurable, acoustic characteristics may identify potential acoustic markers for sound maturation in children’s disordered speech production.