The authors of this study found that speech sound disorder, language disorder, and family risk of dyslexia all have an impact on reading outcomes. When these risk factors are combined, however, literacy outcomes get worse.
The study tracked a large group of 3-year-olds up through age 8, some identified with speech sound disorder (SSD) and some with typical language development. Some of the children in the SSD group also had an identified language disorder (LD) and/or a family risk of dyslexia (FR).
The authors found that children who had speech difficulties at school entry tended to have poorer word reading and phoneme awareness at age 5, but caught up by age 8. The authors concluded that most children with SSD “recover from this early setback.” This wasn’t the case for the children with additional risk factors, however. Poorer reading outcomes were seen in the SSD + LD group, with the most significant impairments in the SSD + LD + FR group. The more risk factors, the more they accumulate, and the larger the impact on literacy outcomes.
So—if your little clients have SSD only, it appears that the impact on literacy is likely to be short-lived (another interesting point—the initial severity of the SSD did not impact literacy outcomes). However, if other risk factors are present (and how will we know if they are? By screening when we do the artic/phono assessment!), this is when we need to have our eyes and ears open. A language disorder or family history of dyslexia should alert SLPs to monitor the child’s early literacy development and to ensure that appropriate interventions are in place.
Hayiou-Thomas, M. E., Carroll, J. M., Leavett, R., Hulme, C., & Snowling, M. J. (2016). When does speech sound disorder matter for literacy? The role of disordered speech errors, co-occurring language impairment and family risk of dyslexia. Journal of Child Psychology and Psychiatry, 58, 197–205.