Is there an interface between explicit and implicit knowledge in L2 acquisition? Rick deGraaff's doctoral dissertation tests this question in an experimental study from a weakinterface position. This position indicates that explicit knowledge has a facilitative role in theacquisition of implicit knowledge when it engages the attention of learners and makes themnotice input features (Schmidt, 1990). De Graaff studies the effect of explicit computer-aidedself-instruction on the acquisition of morphosyntax in Experanto (an artificial language, based onZamenhoff's Esperanto) and Spanish (as a foreign language) by adult native speakers ofDutch. Acquisition is tested in interaction with five intervening factors that constitute acontrolled linguistic, psychological, and pedagogic context (i.e., complexity of structures,rule-based learning in syntax and exemplar-based learning in morphology, familiarity with thestructures, availability of explicit knowledge, and learners' aptitude). Experanto is chosento control for the influence of previous knowledge and contact outside class, and Spanish ischosen to make the results more generalizable.