基于英语学习者语料库的主题词研究

A CLEC-Based Analysis of Key Words and Associates

本研究基于1999年完成的大学英语学习者语料库,旨在考察和分析1)主题词的分布与某一主题的表达存在的关系;2)同一作文题目的主题词之间的联想关系;3)不同题目作文主题词之间的相互关系;以及4)联想词与词语搭配的相互关系。通过研究发现,在学生作文中,同一主题能触发具有共同语用特征和意义联系的词语群,关键主题词与其它主题词存在复杂的联想关系。学生词语运用的成功与否,取决于他们能否构建围绕主题、联想、以及词语搭配关系的词语网络,并在目的语运用中准确地体现这些关系。其意义在于,在外语教学尤其是词汇教学中,围绕某一主题、以语义联想为中心的词汇教学可能比孤立、离散的词汇学习更加有效。

The extraction of the key words for the college English learners is an attempt to find out 1) the distribution of the key words and their relationship with the topical representation; 2) the association between the key words in the texts of the same topic; 3) the interrelationship between the key words in the text of different topics; and 4) the interrelationship between associates and collocates. For this purpose, a key word database composed of separate key word lists from the Chinese College Learner English Corpus (CLEC) has been generated through a comparison of word frequency between two different corpora (p<0.000001). On the basis of the database, a key key word list, i. e.,a list of thekey words with a high frequency of distribution in different texts in the corpus, and the associates, i.e., key words that co-exist with the key key words in the lists with high frequency, have been computed and clumped together to illustrate the learners' knowledge framework of the lexical word patterns and their interrelations. A general survey of the key words and word associations demonstrates that there exists a high frequency of overlapping use of key words in terms of lexical sets in the category of semantic field. Most of the learners' uses of key words are topic-dependent and there is a high vocabulary concentration within the texts of the same topic with regard to the whole corpus. The key words of one subject matter are often inter-related semantically. And the various relationships between the lexical sets for one topic may often attribute to the very theme of the text. The findings have shown that the learners tend to use words in close relation to the meaning organizations in their mental lexicon. And the choice of one word is much determined by how their schematic knowledge about the world is activated and by how the other words in association are chosen in their vocabulary network. For the learners' use of the lexical words, some sets of words are over semantic-loaded and over-generalized and are therefore highly productive. The over-used words are often super-ordinates and therefore less marked in the learners' mental matching of the semantic fields of the two languages. The key words are often used in association with each other and it is possible that the words in association can also be used as collocational links. It has been concluded that the success of vocabulary using depends to a great extent on whether the learners can successfully perceive the complex lexical relations such as topical relations, association, and collocational links and represent them with accuracy in their language production. Such observations are of implication for the EFL teaching in that the lexical words may be better taught when the word association and topical relations are considered. And the new words may be more accessible and made easier for retention if they are delivered on the basis of the subject matter with which the words are connected. Moreover, the findings are also of significance to computer-aided language learning, particular to the learning of vocabulary and English writing.