Prevalence of Speech Delay in 6-Year-Old Children and Comorbidity With Language Impairment

TLDR

The study estimates the prevalence of speech delay among 6‑year‑old monolingual English‑speaking children in the United States using a demographically representative subsample. Data were drawn from the Epidemiology of Specific Language Impairment project, assessing 1,328 children with the Word Articulation subtest and collecting conversational speech samples from 303 participants. Speech delay prevalence was 3.8%, 1.5 times higher in boys (4.5%) than girls (3.1%), varied from 0% to ~9% across demographic strata, and comorbidity with language impairment was 1.3% overall, with 0.51% SLI; among children with persistent speech delay, 11–15% had SLI, and 5–8% of those with persistent SLI had speech delay. The discussion highlights implications of these findings for speech‑language phenotyping in genetics studies.

Abstract

We estimate the prevalence of speech delay (L. D. Shriberg, D. Austin, B. A. Lewis, J. L. McSweeny, & D. L. Wilson, 1997b) in the United States on the basis of findings from a demographically representative population subsample of 1,328 monolingual English-speaking 6-year-old children. All children's speech and language had been previously assessed in the "Epidemiology of Specific Language Impairment" project (see J. B. Tomblin et al., 1997), which screened 7,218 children in stratified cluster samples within 3 population centers in the upper Midwest. To assess articulation, the Word Articulation subtest of the Test of Language Development-2: Primary (Newcomer & Hammill, 1988) was administered to each of the 1,328 children, and conversational speech samples were obtained for a subsample of 303 (23%) children. The 6 primary findings are as follows: (a) The prevalence of speech delay in 6-year-old children was 3.8%; (b) speech delay was approximately 1.5 times more prevalent in boys (4.5%) than girls (3.1%); (c) cross-tabulations by sex, residential strata, and racial/cultural backgrounds yielded prevalence rates for speech delay ranging from 0% to approximately 9%; (d) comorbidity of speech delay and language impairment was 1.3%, 0.51% with Specific Language Impairment (SLI); (e) approximately 11– 15% of children with persisting speech delay had SLI; and (f) approximately 5–8% of children with persisting SLI had speech delay. Discussion includes implications of findings for speech-language phenotyping in genetics studies.