Effect of Complexity on Speech Sound Development: Evidence From Meta-Analysis Review of Treatment-Based Studies

In the current study, we aimed at understanding the effect of exposure to complex input on speech sound development, by conducting a systematic meta-analysis review of the existing treatment-based studies employing complex input in children with speech sound disorders. In the meta-analysis review, using a list of inclusion criteria, we narrowed 280 studies down to 12 studies. Data from these studies were extracted to calculate effect sizes that were plotted as forest plots to determine the efficacy of complexity-based treatment approaches. The outcome variables of interest were improvement on the treated and generalization to the untreated sounds. Meta-analysis revealed that the exposure to complex input not only promoted improvement in production of complex speech sounds (d = 1.08, CI = 0.98–1.19) but also facilitated the production of untreated simple speech sounds (d = 2.69, CI = 1.98–3.54). Overall, the current findings revealed that the exposure to complex input promotes acquisition of both complex and simple speech sounds. The current findings are in line with the models of language learnability. The current findings have implications in the treatment of speech sound disorders.

Clinical Challenges: Assessing Toddler Speech Sound Productions

When assessing toddler speech sound productions, speech-language pathologists (SLPs) must be mindful of several important but not insurmountable limitations inherent to working with this young population for whom speech sound production may be of concern. These limitations include: (1) inconsistencies in recommended connected speech sampling size and phonetic transcription accuracy, (2) the prevalence of typical intraword variability for toddlers, (3) limited information regarding the reliability of informal measures of analysis, and (4) irregularities in available normative data for referencing speech sound development and mastery. This article includes a discussion of these factors, an overview of key assessment tools for single-word and connected-speech sampling, advice for current evidence-based practice procedures, and a thorough but not exhaustive listing of opportunities to improve clinical practice in this area. Despite limitations, SLPs working with toddlers have some tools and resources available to facilitate diagnostic procedures that allow for authentic decision-making regarding access to therapeutic services.