A Developmental Study of Lexico-Phonological Distance in Vocabulary Learning: Evidence From Typically Developing and Learning-Disabled Arabic-Speaking Children.

The present study examines the role of lexico-phonological distance in shaping vocabulary acquisition within Arabic diglossia, drawing on 299 Arabic-speaking children with and without learning disabilities across Grades 1-6. Performance followed a consistent gradient: identical words were easiest; unique words hardest; cognates fell between. This hierarchy held across both receptive and expressive tasks and remained stable over development; the Grade × Word Type interaction was non-significant, indicating that distance-related constraints remain stable with schooling. More telling was the Group × Word Type interaction: the performance gap between typically developing (TD) and learning-disabled (LD) children widened disproportionately for unique words, where the demands of representational construction meet reduced phonological processing resources. A modality asymmetry further qualified the picture: expressive vocabulary proved more sensitive to diglossic distance than receptive vocabulary, consistent with the heavier retrieval demands production places on underspecified representations. Theoretically, the findings are interpreted within MAWRID, which treats linguistic distance as a constraint on representational quality and the Lexical Quality Hypothesis, which links representational precision to lexical access efficiency. These findings implicate lexico-phonological distance as a structural, developmentally persistent constraint on lexical acquisition in Arabic diglossia, with disproportionate consequences for children with compromised phonological resources.