The differential effects of explicit and implicit instruction : focusing on the L2 acquisition of epistemic stance by Japanese EFL learners

This study investigated the effects of explicit and implicit instruction on the interlanguage pragmatic development of Japanese EFL learners. The interventions, which were taught in intact classes, focused on the semantic-pragmatic domain of epistemic stance. The main research questions guiding this study focused on the relative effects of explicit and implicit instruction on the short- and long-term acquisition of epistemic stance. This study also investigated the interaction between type of instruction and the following four variables: (1) mode of communication (writing/speaking); (2) proficiency; (3) difficulty of target forms; (4) individual differences. Eighty-one Japanese EFL learners at a national university took part in all parts of this study. They were divided into explicit and implicit instruction groups for the interventions (4 x 45 minutes), which covered the whole domain of epistemic stance (cognitive verbs, evidential verbs, modal verbs, modal adverbs and epistemic expressions). Free production data (spoken and written) was collected from the participants shortly before the intervention (pre-test), soon after the intervention (post-test) and approximately five months after the intervention (delayed post-test). For both the spoken and written data participants completed two tasks: a picture description and an opinion statement. The learners' data was analyzed using a combination of corpus linguistic techniques and manual analysis, which included the calculation of epistemic token and type scores to measure the frequency and variety of epistemic stance use, respectively. As regards immediate instructional effects, explicit instruction was found to be more effective than implicit instruction. The findings for long-term effects were similar, although a pattern of partial loss of immediate gains was observed. The main findings for the four variables were as follows: (1) both types of instruction had stronger effects on writing than speaking, and particularly in the long-term; (2) proficiency did not play a major role in determining the degree of instructional effectiveness, although typical patterns in the development of the means of expressing epistemic stance were observed; (3) some forms were acquired more easily than others, with the degree of contingency of form-function mappings apparently playing a key role; (4) a minority of learners did not follow the same developmental patterns as the majority. The findings suggest that explicit instruction is the most effective way of helping learners with difficult aspects of L2 pragmatics. However, the partial loss of gains in the long-term suggested that explicit instruction needs reinforcement through practice and/or further input. The degree of difference between learners' use of epistemic stance in writing and speaking demonstrated the role played by different processing conditions on learners' language production. The finding that learner readiness plays a role in the acquisition of epistemic stance has clear implications for teaching. Instruction on epistemic stance also needs to take into account the extent to which contingency affects the learnability of epistemic forms. Finally, the degree of 'hidden' individual variation in the data does not diminish the main findings of this study but does need to be taken into consideration by both teachers and researchers.