The potential impact of literacy intervention on speech sound production in students with intellectual disability and communication difficulties.

A small body of research and reports from educational and clinical practice suggest that teaching literacy skills may facilitate the development of speech sound production in students with intellectual disabilities (ID). However, intervention research is needed to test the potential connection. This study aimed to investigate whether twelve weeks of systematic, digital literacy intervention enhanced speech sound production in students with ID and communication difficulties. A sample of 121 students with ID were assigned to four different groups: phonics-based, comprehension-based, a combination with both phonics- and comprehension-based intervention and a comparison group with teaching-as-usual. Speech sound production was assessed before and after the intervention. The results on the data without the imputed variable suggested a significant positive effect of systematic, digital literacy interventions on speech sound production. However, results from sensitivity analyses with imputed missing data was more ambiguous, with the effect only approaching significance (ps = .05-.07) for one of the interventions. Nonetheless, we tentatively suggest that systematic, digital literacy intervention could support speech development in students with ID and communication difficulties. Future research should be done to confirm and further elucidate the functional mechanisms of this link, so that we may have a better understanding and can improve instruction and the pivotal abilities of speech and reading.