| In recent years, incidental second language vocabulary acquisition through reading has been regarded as the most effective way to enlarge learners' vocabulary. Learners "pick up" lexical knowledge when engaged in reading activities, and vocabulary learning is considered as a by-product during the process. Incidental learning, however, does not mean the absolute absence of attention, because without attention, one can never be engaged in any activities. As Liu Boru points out, under the second language learning circumstances, the automatic and absolutely unconscious vocabulary learning could not exist. Any vocabulary acquired needs learners to have some awareness on the cognitive and metacognitive levels. Incidental vocabulary acquisition, therefore, needs learners' metacognitive involvement.This thesis explores the inner thoughts and feelings of second language learners when they are involved in the process of acquiring second language vocabulary incidentally through reading and examine the relationship between the learners' metacognition and incidental second language vocabulary acquisition through reading.The research is composed of two parts: case study and survey study. In the case study, the subjects are required to keep diaries to record their inner feelings and thoughts when engaged in acquiring second language vocabulary incidentally through reading. The survey study includes a reading comprehension task, a target-word test, a questionnaire, and a vocabulary-size test.The research findings show that good acquirers have much stronger metacongitive awareness than poor acquirers, and that as far as the learners of advanced level is concerned, what mainly affects their scores of the target-word test (incidental vocabulary acquisition) in this research is actually their vocabulary size, although they may have strong metacognitive awareness; for the intermediate level, the relationship between metacognition and incidental vocabulary acquisition is closer than that between vocabulary size and incidental vocabulary acquisition; and for the junior level, their acquisition is rather poor and no significant relationships have been examined. |