Differences in mother–child brain synchronization during storytelling in Literary Arabic versus Spoken Arabic

Introduction Arabic is a diglossic language comprising Spoken Arabic (SA) and Literary Arabic (LA), often leading to Arabic speakers being considered functional bilinguals. While early exposure to LA has been associated with improved reading comprehension, the neurobiological basis of SA–LA processing differences in pre-readers is not well understood. Methods: Thirty-one Arabic-speaking mother–child dyads (children’s mean age = 5.2 years, SD = 0.63; 18 girls) participated in a hyperscanning EEG study during dialogic reading sessions in both SA and LA. Brain–to–brain synchronization was measured using correlation coefficient matrices and compared across language conditions. Synchronization differences were analyzed in relation to vocabulary and listening comprehension scores. Results: Mother–child neural synchronization was greater during SA reading compared to LA. Greater synchronization differences between conditions were associated with slower object-naming speed (r = .473, p = .007). Exploratory region-based analyses revealed associations between synchronization and vocabulary and listening-comprehension measures. Diffusion-map analyses indicated distinct synchronization patterns between SA and LA, with greater joint-attention variability in SA than LA (p = .05), while motion synchronization did not differ between conditions. Conclusion: This study provides neurobiological evidence of reduced neural alignment during LA exposure compared to SA in Arabic-speaking pre-readers. The observed patterns of brain–to–brain synchronization align with findings in bilingual populations, suggesting greater cognitive effort when processing LA. These findings highlight the need for targeted early interventions to support LA acquisition and enhance mother–child neural synchrony during shared reading.