Developmental Language Disorder and Risk of Dyslexia-Can They Be Told Apart?

Abstract

Developmental Language Disorder (DLD) and Dyslexia frequently co-occur. Many studies suggest that children with Dyslexia may also struggle with oral language skills, while those with DLD may also face challenges in word decoding. Both groups of children typically exhibit deficits in phonological processing [phonological awareness, rapid automatized naming (RAN), verbal short-term memory (VSTM)] and verbal working memory (VWM). Despite the increasing number of comparative studies, few have systematically examined these overlaps in children at the early stages of literacy acquisition, and few studies have systematically assessed all oral language subsystems. This study investigates: (a) differences and similarities among children with DLD, children at Risk of Dyslexia (RfD), and typically developing children (TD) in phonological processing (phonological awareness-implicit and explicit-VSTM, RAN), VWM, oral language, and word decoding; (b) patterns of performance across groups; and (c) correlations between phonological processing and VWM skills with oral language and word decoding. The participants were 45 first graders (Mage = 6.8), equally divided into three groups (DLD, RfD, and TD children). Both special groups (DLD, RfD) performed significantly worse than the TD group across nearly all measurements. DLD children showed pronounced oral language and VSTM deficits, while RfD children primarily struggled with decoding and explicit phonological awareness. Group-specific correlations emerged. The findings are discussed in light of the theoretical models of the relationship between DLD and Dyslexia taking into account the specific developmental stage.