The influence of L2 proficiency on orthographic coding flexibility is not a linear pattern: The role of orthographic...

Orthographic coding serves as a foundation underlying word recognition in both first language (L1) and second language (L2) processing. However, empirical research examining how orthographic coding of L2 words, particularly letter position encoding, changes with increasing L2 proficiency remains scarce and inconsistent. Given that L1 research has shown that orthographic regularities shape letter position encoding, the current study aims to investigate whether orthographic regularities (Position Entropy) modulate the change in flexible letter encoding as L2 proficiency increases. Two groups of Chinese-English bilinguals with varying levels of English proficiency participated in a lexical decision task using ERP technology. Analyses of ERP data (P250, N400) indicate that the orthographic regularity of the L2 system influences the degree to which flexibility in orthographic encoding varies as a function of L2 proficiency. Specifically, for L2 words with less uncertainty in letter position distribution (more consistent with the orthographic regularity, indexed by low Position Entropy), the flexibility in orthographic coding increases with L2 proficiency, while for L2 words with high uncertainty in letter position distribution (less consistent with the orthographic regularity, indexed by high Position Entropy), the flexibility in letter coding decreases with language proficiency. Incorporating orthographic regularities into models of orthographic encoding provides a compelling theoretical framework, particularly in the context of L2 word recognition, as it helps clarify how flexibility in letter-position encoding changes with increasing L2 proficiency.