Hojat Ghimatgar

Second-language (L2) sentence comprehension necessitates the real-time integration of semantic and syntactic information. However, how cross-linguistic structural divergences interact with semantic congruity to shape neurocognitive processing remains poorly understood. This study investigated neural processing in Iranian EFL learners using a Rapid Serial Visual Presentation (RSVP) paradigm, recording ERP responses (N400, P600) across four conditions manipulating semantic congruity and L1–L2 syntactic divergence in verb–preposition patterns. Despite ceiling-level behavioural accuracy, ERP results revealed a functional dissociation between semantic and syntactic processing streams. Semantically incongruent items elicited robust, proficiency-invariant N400 effects, indicating declarative memory-based semantic integration. P600 amplitudes, indexing structural reanalysis, varied significantly with syntactic divergence and proficiency: intermediate learners showed attenuated responses relative to advanced learners' native-like sensitivity, supporting the Shallow Structure Hypothesis. These findings suggest L2 development involves stabilisation of declarative semantic mechanisms, followed by gradual, proficiency-dependent recruitment of procedural memory for syntactic parsing, consistent with the Declarative/Procedural model.