Evaluating the effectiveness of speech therapy interventions in children with speech delays

Roughly 7.4% of Canadian children entering kindergarten show some form of speech or language delay, yet the evidence base for choosing one therapeutic approach over another remains surprisingly thin. This research compared five speech therapy interventions head-to-head in a sample of 318 children aged 2 to 6 years, all diagnosed with speech delays of varying types and severity levels. Participants were recruited from 12 community speech-language clinics across the Greater Toronto Area between January 2020 and March 2023. Children were assigned to one of five intervention arms: articulation therapy (n = 68), Prompts for Restructuring Oral Muscular Phonetic Targets (PROMPT; n = 59), naturalistic language intervention (n = 64), parent-mediated intervention (n = 71), and augmentative and alternative communication support (AAC; n = 56). Outcomes were measured using the Clinical Evaluation of Language Fundamentals-Preschool (CELF-P) and the Goldman-Fristoe Test of Articulation (GFTA-3) at baseline, 6 months, 12 months, and 24 months post-enrollment. Results showed that no single intervention outperformed all others across every age group and delay type. Articulation therapy produced the largest gains in children over age 4 with phonological disorders (mean improvement 23.7 points on GFTA-3), while parent-mediated approaches were most effective for children under age 3 (mean improvement 19.4 points on CELF-P). The PROMPT method showed strong results for childhood apraxia of speech but was less effective for other delay types. These findings suggest that matching intervention type to the child's specific profile, rather than applying a one-size-fits-all protocol, yields the best outcomes. Clinicians should consider the child's age, type of delay, and family capacity when selecting a therapeutic approach.