| Previous research on L2 vocabulary acquisition has built on the argument for productive vocabulary as a natural outgrowth of receptive vocabulary acquisition. Such studies have been mainly concerned with the importance of relevant input in promoting L2 learners' vocabulary knowledge, arguing that input is a necessary and sufficient condition for L2 vocabulary acquisition. However, a small number of studies have recently proposed that L2 learners' productive vocabulary knowledge does not develop in the same way that receptive vocabulary knowledge does. These studies claim that input alone does not adequately promote both receptive and productive aspects of L2 vocabulary, and output is as necessary a condition as input for full development of L2 learners' lexical proficiency.; The goal of the present study is to provide empirical evidence in favor of the effects of output on L2 vocabulary acquisition. More specifically, this study aims to address a number of unresolved questions involving output with respect to L2 vocabulary acquisition: (1) What specific functions of output may affect L2 vocabulary development? (2) What learning conditions could be optimal for maximizing those functions of output? In addressing the first issue, this study considers that output could positively affect L2 learners' vocabulary acquisition in terms of three aspects: (a) noticing, (b) retrieval, (c) retention. In terms of the effects of different learning conditions on promoting output, this study examines the interactions of (a) different task types (non-output vs. output), (b) different task performance (non-interaction vs. interaction), and (c) different task sequences (input prior to output vs. output prior to input). The experiment was conducted with ninety-four learners of English in South Korea over the course of eight weeks. The results of ANOVA analyses of vocabulary and written production tests indicated that participants engaged in the task presented with: (a) the output task in (b) the interactive mode achieved significantly higher levels of target vocabulary acquisition than those exposed to the other conditions. The findings of this study suggest the importance of output in developing L2 vocabulary knowledge, as well as argue for the need to consider effective classroom instruction for developing both L2 receptive and productive vocabulary knowledge. |
