Effects Of Instructional Intervention On Vocabulary Learning Through Reading

Taking the information processing model as the theoretical framework, the researcher conducted two experiments to study the effects of instructional interventions on the learning of English vocabulary through reading by Chinese college students. The research focused on interventions with L2 input and learner output. In particular, it investigated the effects of input enhancement, output tasks, and their combined use on the noticing, comprehension, and learning of new words. Each experiment compared the target word knowledge of subjects in four groups: control, input enhancement, output task, and input enhancement plus output task. The different effects of the instructional interventions on learners of different proficiency levels in terms of vocabulary size were also taken into consideration.The first experiment took first-year English majors as the subjects to study the delayed effects of glossing and the blank-filling task. It was found that, generally speaking, the former had no significant effect on the learning of target words, while the latter had a significantly facilitative effect, and their combined use was most facilitative. In learning conditions where no glossing was provided, there was a significant difference between the high- and the low-proficiency learners in their knowledge about the target words. Glossing, as a form of instructional intervention, was more beneficial to the low-proficiency learners, so the gap between them and the high-proficiency learners were significantly narrowed.The second experiment took first-year non-English majors to study the immediate effects of textual enhancement and the sentence translation task. Data on the use of strategies for dealing with target words were also collected by a questionnaire in order to investigate how the instructional interventions affected the learning process. It was found that textual enhancement had no significant effect on the learning of target words, while the sentence translation task had a significantly facilitative effect. Their combined use, though facilitative, was not so effective as the sentence-translation task applied alone. There was no significant difference between the high- and the low-proficiency learners in their knowledge about the target words, but textual enhancement that was added to the sentence translation task had a much greater influence on the former. The difference was proved by the data on strategy use. Studies of strategy use also showed that the sentence translation task encouraged learners to use various active strategies to deal with the target words, while textual enhancement only encouraged learners to infer the meaning of the target words from context more frequently. Meanwhile, textual enhancement did not make any difference to the use of the ignoring strategy.According to the results of the two experiments, output tasks have a significantly facilitative effect on vocabulary learning for both high- and low- proficiency learners, but input enhancement, when applied alone, does not have a significant effect in general. Different forms of input enhancement affect learners of different proficiency levels in different ways: high-proficiency learners are more susceptible to textual enhancement, whereas low-proficiency learners benefit more from glossing, which provides assistance with comprehension of word meaning. When applied in combination with output tasks, different forms of input enhancement also affect vocabulary learning in different ways: glossing has a positive effect on learning, in particular for low-proficiency learners, whereas textual enhancement has a negative effect, in particular for high-proficiency learners.As an external influence, input-based interventions have a limited effect on vocabulary learning because their influence is not so strong as that from learners'internal mechanisms on the allocation of attentional resources. Input enhancement may take effect only when target words receive the allocation of attentional resources from the internal mechanisms as well during reading comprehension processes. However, the type of processing thereby generated may not be efficient for promoting comprehension of the input. Since the role of bottom-up processing based on linguistic cues in reading comprehension is to some extent determined by learners'existing vocabulary knowledge, the extent to which individual learners benefit from input-based interventions is also affected by that factor. In contrast, output-based interventions engage learners, regardless of their existing vocabulary knowledge, in production processes during which target words are processed with focused attention. Language production involves activation of lexical items from the lexicon by matching the lemmas with the meanings and the lexemes with the forms required by output tasks, so learners must adopt various processing strategies in order to establish associations between form and meaning. In this way, output tasks promote the noticing and comprehension and, subsequently, the learning of target words more effectively.The research provides support for the noticing function of output as proposed by the Output Hypothesis and calls attention to the importance of noticing problems with form-meaning mapping in vocabulary learning. In addition, results of the vocabulary knowledge tests in the experiments provide us with a better understanding of word knowledge acquired from reading plus instructional intervention. Finally, the research provides pedagogical implications. In the teaching of the college English extensive reading course, reading tasks can be supplemented with output tasks and, for students of lower proficiency levels, the tasks can be accompanied by glossing. In preparing materials for reading as a general learning activity, glossing and textual enhancement can be applied in combination so that learners may pay attention to the learning of language forms while developing their reading skills.