An Empirical Study On The Relationship Between L2Vocabulary Knowledge And L2Reading Comprehension Of Medical Postgraduates

In the field of second language vocabulary acquisition, linguists have been interested in the vocabulary threshold hypothesis of second language learners, that is, the minimal level of vocabulary knowledge that L2learners need to achieve adequate comprehension of written texts (Laufer&Ravenhorst-Kalovski,2010:15). Studies by foreign researchers have shown that the minimal threshold level is about5000word families which can cover95%of running words in texts, and a maximum one is about8000word families with98%text coverage. Studies at home have mainly paid attention to the L2vocabulary proficiency of undergraduate students and its relationship with L2reading comprehension. However, little is known about the L2vocabulary size of the postgraduates and its relationship with L2reading comprehension.Therefore, the thesis attempts to explore the relationship between L2vocabulary knowledge and L2reading comprehension of Chinese medical major postgraduates. Three questions are addressed:1) What is the vocabulary proficiency of the medical postgraduate students at CET6level?2) Is there any gender difference in L2vocabulary knowledge of the students?3) What is the relationship between L2vocabulary knowledge of the students and their L2reading comprehension?The subjects of the study were228first-year postgraduates in a medical college and they took part in two vocabulary tests and a sampled reading comprehension test of CET6. The results can be listed as follows:1) On average, the overall vocabulary size of the postgraduates is5184words, which merely reaches the basic vocabulary requirements of the2007College English Curriculum. Both the vocabulary proficiency and growth rate of the subjects are lower than those of the graduates from key institutions of science and technology. The students’ text vocabulary size is also very small with an average text coverage of48.84%, far from the recommended threshold levels ranging from95%-98%. In addition, the postgraduates have a limited number of word meanings.2) Gender difference to some extent affects L2learners’ vocabulary proficiency. The female students’ general vocabulary size is significantly higher than that of the male students; but no statistical difference is found in terms of the text vocabulary size. 3) The correlation analysis indicates that overall vocabulary size, text vocabulary size and reading comprehension scores are correlated with each another. Overall vocabulary size is intermediately correlated with text vocabulary size. However, both of the two variables are weakly correlated with the subjects’ reading scores. Then, among the three test types of the reading comprehension test in the present study, i.e. Yes or No, Blank Filling and Multiple Choices, there is only a low correlation between Blank Filling questions and vocabulary knowledge of the students.The study concludes that the correlation between L2vocabulary knowledge and L2reading comprehension is not as high as that in previous studies. One of the possible reasons can be that the L2vocabulary proficiency of the subjects in this study is relatively lower; and there are large individual differences in their overall vocabulary size and text vocabulary size. Therefore, the first suggestion is that great importance should be attached to L2vocabulary instruction for non-English major postgraduates. Teachers are supposed to employ various methods to improve the students’ vocabulary proficiency. Second, the advantages for female students in L2vocabulary acquisition can be applied to L2vocabulary teaching. Finally, it is necessary to take L2learners’ actual vocabulary proficiency into consideration in reading comprehension.