The Effects Of Vocabulary Knowledge On Reading Comprehension: An Empirical Study

English vocabulary acquisition is a key component in the English language acquisition, and it is also the basis of other skills, such as listening, speaking, reading, writing and translating. Developing a rich vocabulary is a top priority and a long-term challenge for English learners. Vocabulary is so important that it opens new frontiers for foreign language researchers and teachers.There are many studies of vocabulary (especially vocabulary size) or reading comprehension both in China and abroad, but there are some of the relationship between the two. In recent years, vocabulary studies are focused either on breadth of vocabulary knowledge, which pays attention to learners' vocabulary size, or depth of vocabulary knowledge, which explores the development of various dimensions of individual words. Traditional vocabulary studies are mainly about vocabulary size and neglect depth of vocabulary knowledge.Given such situation, the present study attempts to investigate the relationship between vocabulary knowledge (breadth and depth) and reading comprehension among English majors in China where English is learned as a foreign language. 52 second-year English majors in the School of Foreign Languages and Literature of Shandong University took part in the study, and three tests were conducted respectively examining their vocabulary size, depth of vocabulary knowledge and reading comprehension. Vocabulary size was tested by a new version of the Vocabulary Levels Test originally designed by Nation (1983, 1990), and now revised and expanded and presented validity evidence by Schmitt and Clapham (2001). Depth of vocabulary knowledge was tested by a paper which adopted Read's (1993, 1997, 1998) Word Associates Format. The reading comprehension test was a standardized multiple-choice test taken from the reading comprehension section of TEM 4 (Test for English Majors—Band Four) (2006). SPSS 13.0 (Statistical Package for the Social Sciences) was employed for Pearson correlation analysis and multiple regression analysis.The results showed: (1) there is high positive correlation among breadth of vocabulary knowledge, depth of vocabulary knowledge and reading comprehension. (2) In addition to the prediction of breadth of vocabulary knowledge on reading comprehension, depth of vocabulary knowledge can make a unique contribution to reading comprehension.Based on results of the present study, it is revealed that vocabulary learning is much more than learning as many words as possible. Learners must learn to master deep knowledge concerning individual words in various aspects. To improve reading comprehension, at least two components of vocabulary depth knowledge need serious attention in making EFL curricula. First, in addition to primary meanings of words, synonymy and polysemy are also important elements that should be introduced in the classroom. Second, syntactic properties of words, in particular their collocational relations with other words, are also well worth learners' attention, since the levels of these aspects of word knowledge are strongly associated with those of reading comprehension. To sum up, it is very important to put emphasis on both the breadth and the depth of vocabulary knowledge in English vocabulary teaching and learning.