Investigates the relationship between lexical semantics and derivational morphology in the acquisition of causative/inchoative-related verbs in Turkish as a second language (L2) by Spanish and English speakers. Suggests that L2 learners are attuned to the rich morphology of Turkish and that the acquisition of derivational morphology and lexical semantics are not dissociated in these interlanguage grammars. (Author/VWL)