The role of first language use in second language grammar teaching and learning

We investigated the impact of explicit instruction (EI) about the L1 on the L2 learning of the French Imparfait. L2-only and L2+L1 explicit instruction were compared by providing (i) explicit information about the L2 with practice in interpreting it  and (ii) additional explicit information and practice about equivalent L1 features. In a pre-, post-, delayed post-test design, results from online and offline measures showed that providing additional L1 explicit information and practice improved not only offline L2 accuracy, but also speed of online L2 processing. In light of previous research arguing that EI and practice play an important role in L2 learning (DeKeyser & Prieto Bontana, 2015), we will contextualize our findings in terms of L1-L2 differences (McManus, 2011, 2013, 2015), but also the roles played by EI and practice (Marsden & Chen, 2011).