A Study On The Correlations Among ESL Learners’ Breadth Of Vocabulary Knowledge, Depth Of Vocabulary Knowledge And Oral Proifciency

The importance of vocabulary in second language acquisition is undeniable, and it has long been a subject which arouses the interest of many linguists. Many scholars have carried on lots of empirical studies to investigate the role vocabulary plays in second language acquisition, and they have got many different results. This thesis also focuses on vocabulary, but different from other scholars, this thesis explores the correlation between oral proficiency and word knowledge.Word knowledge is considered to be multi-dimensional and consists of many aspects of knowledge. This thesis chose the two primary dimensions, breadth of word knowledge and depth of word knowledge and studied the correlations between them and their correlations with oral proficiency. This empirical study was carried on thirty-two subjects who were going to take part in one of the standard international English level tests-IELTS(The International English Language Testing System). The speaking score of this exam was used as a token of oral English level; breadth of word knowledge was tested by the new version of Vocabulary Levels Test, originally designed by Nation, and now revised and expanded by Schmitt and Clapham; depth of word knowledge was tested by an economical and reliable measure proposed by Read, Word Associates Test, to probe the extent to which learners are familiar with the meanings and usages of target words.The result shows there is a high correlation between breadth of word knowledge and depth of word knowledge, which can further prove the results other scholars have got. The significant result of this study is the tested positive correlation between breadth of word knowledge and oral proficiency and even higher correlation between depth of word knowledge and oral proficiency.The implication of this study lies in it calling attention to the importance of word knowledge in deciding second language learners’ oral proficiency and inspiring them to pay close attention to the semantic value, part of speech, collocation and other aspects of depth of word knowledge. In addition the result shows subjects’depth of word knowledge lags far behind their breadth of word knowledge, so many suggestions are proposed to ensure second language learners can acquire depth of word knowledge efficiently and skillfully.