Depth versus Breadth of Lexical Repertoire: Assessing Their Roles in EFL Students’ Incidental Vocabulary Acquisition

This study explores the roles of depth and breadth of lexical repertoire in L2 lexical inferencing success and incidental vocabulary acquisition through reading. Students read a graded reader containing 13 pseudo-words and attempted to infer the meanings of underlined target words. The Word Associates Test (WAT, Read, 2004) and the Vocabulary Levels Test (Schmitt, Schmitt, & Clapham, 2001) were administered to measure depth and breadth of lexical repertoire respectively. To rate retention of inferred meanings, I administered the Vocabulary Knowledge Scale (VKS, Paribakht & Wesche, 1996, 1997) with a repeated measure design. The results indicated that (a) both breadth and depth of lexical knowledge correlated positively with long-term retention of inferred word meanings. However,depth of vocabulary knowledge indicated a higher correlation; and (b) scores on both breadth and depth of vocabulary knowledge had a significant positive correlation with success of lexical inferencing through reading, but depth of vocabularyknowledge was a stronger predictor of inferencing success.