L1 explicit instruction can improve L2 online and offline performance

This study investigated the effectiveness of providing L1 explicit information (EI) with practice for making more accurate and faster interpretations of L2 French Imparfait (IMP). Two treatments were investigated: (a) “L2-only,” providing EI about the L2 with L2 interpretation practice, and (b) “L2+L1,” providing the exact same L2-only treatment and including EI about the L1 (English) with practice interpreting L1 features that are equivalent to the IMP. Fifty L2 French learners were randomly assigned to either L2-only, L2+L1, or a control group. Online (self-paced reading) and offline (context-sentence matching) measures from pretest, posttest, and delayed posttests showed that providing additional L1 EI and practice improved not only offline L2 accuracy, but also the speed of online L2 processing. To our knowledge, this makes original and significant contributions about the nature of EI with practice and the role of the L1 (Tolentino & Tokowicz, 2014), and it extends a recent line of research examining EI effects in online sentence processing (Andringa & Curcic, 2015).