Sequencing Deficits and Phonological Speech Errors, But Not Articulation Errors, Predict Later Literacy Skills

Purpose: Speech sound disorder (SSD) in conjunction with a language disorder has been associated with poor literacy acquisition; however, no study has evaluated whether articulation, phonological, or sequencing skills are differentially related to reading skills. Therefore, this study examined the relationship between speech error types at ages 5-6 years and literacy at ages 7-9 years. Phonological errors were hypothesized to predict phonological awareness (PA) and literacy even while accounting for other speech error types and language skills. Method: One hundred twenty-three children, 86 with a history of speech impairment, completed a battery of speech, language, and literacy tests at ages 56 years and again at ages 7-9 years. Speech production at ages 5-6 years was analyzed, and indices of articulation errors, phonological errors, and sequencing deficits were obtained. The relationships of these error types to concurrent language and preliteracy skills and to later literacy outcomes were assessed. Results: As expected, phonological, but not articulation, errors at ages 56 years predicted concurrent PA and letter knowledge, as well as literacy at ages 7-9 years, even while accounting for language skills. Surprisingly, of all the error types, sequencing deficits showed the strongest relationship with PA (ages 5-6 years) and literacy (ages 7-9 years). Conclusions: These results suggest that some components of SSD uniquely predict preliteracy and literacy skills, even when controlling for language ability. Future investigations should examine further the association between sequencing deficits and literacy skills, test whether observed relationships hold at younger ages, and evaluate the efficacy of integrating literacy interventions into speech therapy to reduce later reading difficulties.