The effects of input enhancement and explicit instruction on developing Iranian lower-intermediate EFL learners’ explicit knowledge of passive voice

The importance of teaching explicit knowledge of grammar has been one of the most controversial issues in L2 instruction. Despite the existence of considerable number of studies on different methods of grammar instruction, very few studies have investigated the role of explicit instruction and input enhancement on developing EFL learners’ explicit knowledge of grammatical structures. Therefore, this study is an attempt to investigate the effects of input enhancement and explicit instruction on developing Iranian EFL learners’ explicit knowledge of simple present and simple past passive voice. To this end, 48 lower- intermediate EFL students participated in the present research and a pretest-posttest quasi experimental design with two experimental groups and a control group was adopted. While the participants in the explicit instruction group received explicit instruction on selected passive forms, those in the enhanced input received the same passages but the target passive forms were enhanced via bolding and underlining, and the control group received the same texts but in the original form with no enhancement or explicit instruction. To measure participants’ explicit knowledge of the target passive voice, two valid measures including untimmed grammaticality judgement test (UGJT) and metalinguistic knowledge test (MKT) were used. One-way ANOVA results indicated the superiority of the explicit instruction in developing explicit knowledge of passive voice. The findings have some pedagogical implications for EFL teachers and material developers. © 2018, The Author(s).