The Roles Of Depth Of Vocabulary Knowledge In Reading Comprehension

One of the fundamental goals for English learners is to extend their vocabulary knowledge. Substantial lexical knowledge in breadth and depth is always a prerequisite to the performance of language skills such as reading and writing. This present study explores the relationships between vocabulary knowledge and reading comprehension in learning English as a foreign language (LEFL) and thus provides a correlation study from an applied linguistic perspective.Although the relationship is intuitively obvious, it is not easily supported by empirical evidences, especially in LEFL in China. Furthermore, within this area, the two ends of the scales are rather unbalanced: the greater part of the literature has been focused on how L2 learners acquire their vocabulary through reading, while, except for a very limited number of studies, few studies have attempted to determine what role vocabulary knowledge plays in L2 reading comprehension. Even within the small number of studies that have assessed the relationship between vocabulary knowledge and reading comprehension in L2, the majority focus, again, on breadth of vocabulary knowledge. Little recognition is accorded to the roles depth of vocabulary knowledge plays.This thesis aims to examine the roles of depth, as well as breadth of vocabulary knowledge in assessing the performance of two groups of LEFL at different proficiency levels in carrying out general academic reading comprehension tasks. The thesis consists of six chapters. Chapter One is a general introduction, providing some background and overview of the topic. It mainly introduces the purpose of choosing the topic, the definition and measurement issues of breadth and depth of vocabulary knowledge. Chapter Two reviews the previous research on breadth and depth of vocabulary knowledge, on the relationship between breadth and depth, and on the relationship between word knowledge (mainly breadth dimension) and reading comprehension. Chapter Three outlines the theoretical bases from perspectives of vocabulary-reading connection and reading process. In this chapter, Anderson & Freebody's (1985) instrumentalist hypothesis, aptitude hypothesis, knowledge hypothesis, Mezynski's (1983) access hypothesis, and Adams's (1990) model of reading process are briefly presented. In Chapter Four, the hypotheses, methodology, instruments, and procedures of the study are elaborated. The students in two classes in Grade 8 in my school take the four tests of vocabulary size, depth-of-vocabulary- knowledge, morphological knowledge and reading comprehension. Chapter Five analyzes all the data collected by using multivariate analyses. As a result, I conclude that (1) scores on the vocabulary size, depth of vocabulary, and reading are highly, and positively correlated; (2) scores on depth of vocabulary knowledge can make a unique contribution to the prediction of reading comprehension levels, in addition to the prediction afforded by vocabulary size scores. Chapter Six presents implication for language teaching, the limitation of the study and suggestion for future research.The findings from this study not only confirm the roles of breadth of vocabulary knowledge, but also call for recognition of the importance of improving depth of vocabulary knowledge in LEFL processes.