A Study Of The Academic Vocabulary Knowledge Of Chinese Postgraduate Students

Extensive analysis of corpora has revealed the prevalence and the importance of academic vocabulary in academic and research settings. Given that one of the objectives of postgraduate English teaching in China is to facilitate postgraduate students with adequate language skills so that they can succeed in future academic learning and communication, this study is designed to investigate the students'academic vocabulary knowledge and the interrelationships of its various dimensions so as to provide suggestions to better prepare them for their academic learning in English.In light of previous theoretical and empirical studies of L2 vocabulary acquisition, a tentative conceptual framework of academic vocabulary knowledge has been constructed for the present study. This framework incorporates four basic dimensions: receptive size, productive size, depth of receptive word knowledge, and depth of productive word knowledge. In the dimension of the depth, two components, meaning and collocation, have been particularly investigated.Relevant data were collected during two stages. During the first stage, three hundred and sixty postgraduates from two major universities in Shanghai sat a series of vocabulary tests. Specifically, the adapted Vocabulary Levels Test by Schmitt et al. (2001) was employed for the postgraduates'receptive academic vocabulary size, the adapted version of the Productive Levels Test (Laufer & Nation, 1999) for their productive academic vocabulary size, the Depth of Receptive Vocabulary Knowledge, developed on the basis of Read's (1993, 1998) and Qian's (2004), for their depth knowledge of receptive academic vocabulary. During the second stage, the academic writings of more than one hundred postgraduate students from seven different subject fields were collected in order to build a learner corpus of academic English—Postgraduate Learner Corpus of Academic English (PLCAE). Analysis of the collected data has yielded the following findings:1) Chinese postgraduate students have a large receptive academic vocabulary. On average, they know approximately ninety-two percent of the words contained in Coxhead's (2000) Academic Word List (AWL), which is higher than the proportion of the words they know at the word frequency levels of 3,000, 5,000 and 10,000. Nevertheless, these students may still encounter vocabulary problems when they read academic English texts owing to their limited vocabulary size at the 5,000 and the 10,000 levels.2) The postgraduate students'productive size of academic vocabulary is much smaller than their receptive size. On average, they only produce thirty-eight percent of the word families in the AWL, which is lower than the proportion of the words they produce at the 3,000-word level. This indicates that even though the highest recognition rate is at the AWL, most of the words they can produce are high frequency words, e.g. words at the 3,000-word level.3) The gap between productive and receptive size is larger in academic vocabulary than that in high frequency vocabulary; and the gap narrows with the advancement of the postgraduate students'English proficiency.4) The postgraduate students demonstrate a partial knowledge with regard to the depth of receptive academic vocabulary knowledge. Most academic words are neither completely acquired nor completely new to the students. In addition, the students'knowledge of word meanings outperforms their knowledge of collocation.5) Positive and significant correlations exist among five variables, including receptive/productive size of academic vocabulary, depth of receptive academic vocabulary knowledge, and receptive/productive size of general vocabulary, r ranging from 0.394 to 0.640. The correlations among depth of academic vocabulary knowledge, receptive academic vocabulary size and productive academic vocabulary size support the hypothesis, proposed by Melka (1997) and Henriksen (1999), that depth of word knowledge is an important factor for the process of receptive-productive development. Nonetheless, the relatively stronger correlations between two groups of words of the same type of word knowledge, i.e. receptive academic vocabulary size vis-à-vis receptive general vocabulary size, productive academic vocabulary size vis-à-vis productive general vocabulary size, reveal that academic vocabulary knowledge is closely related to general word knowledge. They also imply that Henriksen and Melka's hypothesis may over-simplify the relationship between receptive and productive vocabulary. In the process of receptive-productive development, the effect of type of word knowledge should not be neglected.6) Evidence from the learner corpus of PLCAE also shows that Chinese postgraduate students have a partial knowledge of productive academic vocabulary. With regard to the component of word meaning, the students tend to use the meanings that bear some specialized information in their academic writing, while the senses that play cohesive roles in organizing academic texts are either underused or not used at all.The students also show deficiency in their knowledge of collocation. They are likely to underuse the collocates that express stance or play cohesive roles and to use the collocations that are not typical in native speakers'academic writing.The findings of this study suggest that the relationship among various dimensions of L2 learners'word knowledge is not as simple as has been described in previous literature. Given that L2 vocabulary acquisition research is still in its early phase, in the process of modeling L2 vocabulary acquisition, a cautious and critical attitude to the research findings in this field is recommended.This study also identifies an important academic skill that is not well acquired by Chinese postgraduate students. The potential of academic vocabulary has not been fully addressed in postgraduate English teaching in China. Attention has no longer been paid to academic words once their meaning is known. It is suggested that syllabus designers, material developers, classroom teachers, and the students themselves should be aware of the fact that vocabulary knowledge is not an all-or-nothing phenomenon and treat this set of important words in a variety of complementary ways in order to improve the students'receptive and productive use of them.In addition, the learner corpus of academic English developed in the present study provides a useful tool for researchers who are interested in exploring postgraduates'academic writing. This corpus can assist researchers to develop a clearer knowledge about the lexis, discourse, and pragmatics of the students'academic writing.