Lexical organization in typically developing children and children with Down syndrome: a structural network analysis

Lexical network analysis provides a powerful framework for examining how words are organized in the mind, as well as the semantic, categorical, and associative links that structure the mental lexicon. This study investigates the organization, structural properties, and types of lexical relations present in individual lexical networks of typically developing children and children with Down syndrome. Lexical relations were examined using network-based structural analyses derived from co-occurrence patterns, and measures of density, centrality, modularity, hubs, semantic clustering, and word-type distributions were computed, together with the analysis of taxonomic and thematic relations. The results reveal significant differences between the two populations, despite comparable vocabulary sizes. These differences are discussed in terms of variation in the mechanisms underlying lexical acquisition and organization, as well as the role of experience in psycholinguistic development. Overall, this study provides empirical evidence on early lexical organization in typical development and Down syndrome, with implications for theories of language development and for educational and therapeutic approaches aimed at strengthening vocabulary.