A sentence interpretation experiment based on Bates and MacWhinney's CompetitionModel was administered to L2 learners of English and Chinese at three different stages oflearning. The main purposes of the research were (a) to examine how transfer patterns at thesentence processing level change as a function of proficiency and (b) to investigate whether orhow transfer patterns found in Chinese EFL learners (i.e., native speakers of a semantics-basedlanguage learning a syntax-centered target language) differ from those found in English CFLlearners (i.e., native speakers of a syntax-based language acquiring a semantics-centered one). Theresults show that transfer patterns do vary as a function of proficiency, and that Chinese EFLlearners and English CFL learners display somewhat different patterns of developmental change insentence processing transfer.