Syntactic analyses on the be-insertion structure and suggestions for the L1 transfer research

The nontargetlike insertion of be-verbs before thematic verbs is often analyzed as a transfer of topic-prominence from learners’ L1, due to the perceived similarity between inserted be-verbs and the topic marker -un/nun in Korean. However, attributing L1 transfer based solely on superficial dissimilarities with the target grammar and similarities with the L1 can be problematic. To address these limitations, this study proposes multiple syntactic structures for clauses containing unnecessary be-verbs. This analysis demonstrates that a single surface structure can arise from multiple underlying syntactic forms. Additionally, following Jarvis (2000, 2006), this study emphasizes the need for L1 transfer research to incorporate cross-L1 comparisons and track developmental changes across proficiency levels within the same L1 group.