Using experimental data from adult and child non-native language acquirers (L2ers), this paper addresses "interface issues" in language acquisition in two different ways. First, it examines the acquisition of direct object scrambling in Dutch, a phenomenon which involves the interaction of at least two different modules of language, i.e., syntax and semantics. Second, it considers the interface between language and cognition in terms of the potential effect of cognitive maturity on the language acquisition process. Specifically, we examine data from adult and child non-native acquirers (L2ers) of Dutch, comparing these two groups both with each other and to relevant first language (L1) data. The results of these comparisons indicate that not only are both groups of L2ers able to acquire the particular aspect of scrambling under investigation, the developmental stages which they pass through are identical. Implications for the status of the syntax-semantics interface in L2 acquisition are also discussed. (Contains 13 footnotes.)