Bridging the Gap Between Language and Literacy: Evidence from Interventions in Young Greek-Speaking Children with Developmental Language Disorder

Developmental language disorder (DLD) is a neurodevelopmental condition characterized by persistent difficulties in language acquisition, affecting both comprehension and production, and typically emerging in early childhood through deficits in morphosyntax, vocabulary and phonology. Although distinct from Specific Learning Disabilities, particularly in reading, the two conditions often co-occur, sharing underlying mechanisms and leading to overlapping challenges such as impaired phonological processing, limited vocabulary, weak narrative skills, and reading comprehension difficulties. This study examined the effects of two intervention programs—semantic versus phonological—on oral language skills in 107 Greek children with DLD aged 4;1–5;10. Participants were randomly assigned to a phonological (n = 35), a semantic (n = 35), or a control group (n = 37). Interventions were delivered individually twice weekly over 16 weeks (32 sessions). Language performance was assessed at baseline, immediately post intervention, and at a four-month follow-up using standardized measures. Repeated-measures ANOVAs evaluated within- and between-group differences. Results indicated differential but complementary effects of the two interventions: phonological training enhanced greatly phonological awareness (d = 0.80) and was associated with short-term gains in vocabulary, whereas the semantic intervention produced sustained improvements in vocabulary (d = 0.45). While the semantic group performed slightly better than the control group, no statistically significant difference was found between the two intervention groups, suggesting broadly comparable but domain-specific benefits. These findings highlight the value of systematic interventions and indicate that combining semantic and phonological approaches may optimize language and literacy development, providing evidence-based guidance for early intervention in preschool children with DLD.