The incidence of speech sound disorders refers to the number of new cases identified in a specified period. The prevalence of speech sound disorders refers to the number of children who are living with speech problems in a given time period.
Estimated prevalence rates of speech sound disorders vary greatly due to the inconsistent classifications of the disorders and the variance of ages studied. The following data reflect the variability:
- Overall, 2.3% to 24.6% of school-aged children were estimated to have speech delay or speech sound disorders (Black, Vahratian, & Hoffman, 2015; Law, Boyle, Harris, Harkness, & Nye, 2000; Shriberg, Tomblin, & McSweeny, 1999; Wren, Miller, Peters, Emond, & Roulstone, 2016).
- A 2012 survey from the National Center for Health Statistics estimated that, among children with a communication disorder, 48.1% of 3- to 10-year old children and 24.4% of 11- to 17-year old children had speech sound problems only. Parents reported that 67.6% of children with speech problems received speech intervention services (Black et al., 2015).
- Residual or persistent speech errors were estimated to occur in 1% to 2% of older children and adults (Flipsen, 2015).
- Reports estimated that speech sound disorders are more prevalent in boys than in girls, with a ratio ranging from 1.5:1.0 to 1.8:1.0 (Shriberg et al., 1999; Wren et al., 2016).
- Prevalence rates were estimated to be 5.3% in African American children and 3.8% in White children (Shriberg et al., 1999).
- Reports estimated that 11% to 40% of children with speech sound disorders had concomitant language impairment (Eadie et al., 2015; Shriberg et al., 1999).
- Poor speech sound production skills in kindergarten children have been associated with lower literacy outcomes (Overby, Trainin, Smit, Bernthal, & Nelson, 2012). Estimates reported a greater likelihood of reading disorders (relative risk: 2.5) in children with a preschool history of speech sound disorders (Peterson, Pennington, Shriberg, & Boada, 2009).