| Previous researches on L2 vocabulary acquisition 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 1) to find out the effects of the input-only and input plus output activities on L2 vocabulary acquisition of both receptive and productive aspects and 2) to investigate which learning conditions are more effective in promoting L2 vocabulary acquisition concerning the sequence of learning tasks..To address the above issues, empirical research was conducted with 121 the second year vocational college students learning English as a foreign language in China. The subjects belonged to three intact classes with similar average levels of English proficiency. Three intact classes are randomly assigned to 1) input-only group (N=41) 2) input-output group (N=40) and 3) output-input group (N=40). All participants in the experimental groups completed the vocabulary pretest–treatment– immediate vocabulary posttests– delayed vocabulary posttests. And all the subjects performed two written production posttests after the treatment. Nine participants selected from each of the 3 experimental groups participated in an informal interview.The data were analyzed by using SPSS, with independent-samples t-test to investigate whether there was any significant difference between the groups for each time factors, and with paired-samples t-test to compare mean score between time factors for each group. The results of the current study have shown that 1) the input-only treatment was more effective in promoting short-term vocabulary learning effects. However, the input-only treatment was not as effective as the input plus output treatment in terms of the long-term retention of words and transference of comprehended words to productive use. 2)The output prior to input task sequence and the input prior to output task sequence had no significant difference on the participants'target vocabulary acquisition.The implications of the current study are that output practice should necessarily be included in L2 vocabulary instruction in order for full development of learners'vocabulary knowledge, because the output treatments were a necessary condition for increasing learners'noticing of words they needed to know in order to express their ideas, in facilitating retrieval of learned words, and in extending the retention duration of words they have acquired. In particular, the fact that the output treatments significantly affected participants'acquisition of target vocabulary in the long term and improve productive vocabulary acquisition. This proved that output practice increases the chances for the reorganization and restructuring of information, and plays a crucial role in developing productive language skills. But, it also needs to be pointed out that the input condition was an important factor in developing L2 learners'vocabulary knowledge, in the sense that it provided necessary information to determine in which contexts L2 vocabulary should properly be used. |
