Dimensions Of Vocabulary Knowledge And Their Predictive Power For L2Reading Comprehension

The study on Vocabulary knowledge is of great value in the field of SLA. In light of the current development in L2vocabulary acquisition, vocabulary knowledge is no longer viewed as a one-dimensional construct, but a multi-dimensional framework. As for the relationship between vocabulary knowledge and L2reading comprehension, researchers have made some exploration and formulated some important theories. However, most researches use very simplified operational definitions of vocabulary knowledge and lack a detailed exploration of the multi-facets of vocabulary knowledge when investigating its relationship with L2reading comprehension. Therefore, a more comprehensive framework is needed in order to understand the dimensionality of vocabulary knowledge and its relationship with L2reading comprehension. The present study explores the relationship within and between dimensions of vocabulary knowledge (i.e., the breadth and depth of vocabulary knowledge) and their predictions for L2reading comprehension.Specifically, this empirical study serves to solve the following research questions:1. What’s the relationship between components of the breadth of vocabulary knowledge?2. What’s the relationship between components of the depth of vocabulary knowledge?3. What’s the relationship between the two dimensions (i.e., the breadth and depth of vocabulary knowledge) of vocabulary knowledge?4. How do different dimensions of vocabulary knowledge predict L2reading comprehension?(1) How does the breadth of vocabulary knowledge predict L2reading comprehension?(2) How does the depth of vocabulary knowledge predict L2reading comprehension?In the present study, the breadth dimension includes receptive vocabulary size and productive vocabulary size while the depth dimension consists of polysemous knowledge, syntagmatic knowledge, paradigmatic knowledge and morphological knowledge.141sophomores from5intact classes of Nanjing University of Technology, Nanjing Xiaozhuang University and Huaiyin Institute of Technology, chosen as subjects, took part in the experiment. The experiment comprised two test papers. Test paper one was vocabulary knowledge test, where the breadth of vocabulary knowledge test was made up of40receptive vocabulary items and40productive vocabulary items, and the depth of vocabulary knowledge test was made up of20polysemous knowledge items,20syntagmatic knowledge items,20paradigmatic knowledge items and20morphological knowledge items. Test paper two was a reading comprehension test with15multiple choices and5short answer questions. All the subjects took the vocabulary knowledge test and reading comprehension test within two and a half hours in the class session.The present study conducted the Pearson correlation analyses to answer the first two research questions, a canonical correlation analysis to answer the third research question, and the stepwise multiple regression analyses to answer the fourth research question. The major conclusions drawn from the present study are listed below:1. Within the breadth of vocabulary knowledge, the correlation coefficient between productive vocabulary size and receptive vocabulary size is relatively high(r=.667, p <.01).2. Within the depth of vocabulary knowledge, though the correlations between morphological knowledge and other facets reached a significant level, the coefficients are all low (r<.500). The correlations between other facets of depth of vocabulary knowledge are all high (r>.500)3. The correlation between the two dimensions of vocabulary knowledge (i.e., the breadth and depth of vocabulary knowledge) is very strong. The canonical correlation coefficient is as high as.823(p<.01).4. Both the breadth (R2=.502) and depth (R2=.452) of vocabulary knowledge can predict much of the variance of L2reading comprehension, and the breadth dimension can predict L2reading comprehension a little more (adjusted R2=49.5%as compared to44%for the depth dimension).(1) Within the breadth of vocabulary knowledge, productive vocabulary size (β=.467) predicts L2reading comprehension more than receptive vocabulary size(β=.305) does. The unique explanation power of productive vocabulary size for L2reading comprehension is12.1%, and that of receptive vocabulary size is5.2%.(2) Within the depth of vocabulary knowledge, polysemous knowledge (β=.327) plays a bigger role than syntagmatic knowledge (β=.259) and paradigmatic knowledge (β=.213) do. The unique explanation power of each for L2reading comprehension is7.1%,3.6%and2.4%separately. Morphological knowledge makes no prediction for L2reading comprehension.The present study has important theoretical, methodological, and pedagogical implications. Theoretically, it contributes to a better understanding of the dimensionality of vocabulary knowledge and its relationship with L2reading comprehension, overcoming the problems arising from simplifying the construct of vocabulary knowledge that the previous studies had. Methodologically, this study is featured by multi-methods. It uses the Pearson correlation analyses to explore the componential relationships within the breadth and depth of vocabulary knowledge, a canonical correlation analysis to investigate the relationship between the breadth and depth dimensions of vocabulary knowledge, and the stepwise multiple regression analyses to examine the predictive power of the breadth and depth of vocabulary knowledge for L2reading comprehension. Pedagogically, it makes both L2teachers and learners realize that vocabulary knowledge is no longer a one-dimensional construct but a multi-dimensional one. Therefore, in an attempt to improve L2learners’ reading ability, both L2teachers and learners should pay attention to the growth of each component of vocabulary knowledge. Great importance should also be attached to the accumulation of other components of vocabulary knowledge like polysemous knowledge, paradigmatic knowledge and syntagmatic knowledge in addition to the enlargement of vocabulary size.