Abstract
This study examined the role of output-first presentation of vocabulary tasks in noticing lexical items and enhancing vocabulary knowledge of EFL learners. The participants were 103 elementary level female Iranian EFL learners who were randomly divided into three groups: input-only, input-output, and output-input groups. After all participants took a placement test and a vocabulary pretest, the input-only group of learners received only input tasks, while the members of the other two groups received both input and output tasks in different sequences. All participants then took a vocabulary posttest. Comparison of input-only group with the other two groups showed that participants in the input plus output groups outperformed input-only group in the vocabulary post-test. The results of t-test and Mann-Whitney test indicated that output-input group performed better than the input-output group in both overall vocabulary posttest and the productive vocabulary section of the test. Moreover, the results of the semi-structured interview revealed the positive influence of output-first presentation of vocabulary tasks on noticing the gap in lexical knowledge. The findings of this study suggest presentation of vocabulary tasks in the sequence of output prior to input in order to enhance noticing vocabulary knowledge gap and develop vocabulary knowledge.