The impact of vocabulary level on EFL reading comprehension performance

Introduction Vocabulary knowledge performs a prominent role in future possibilities and people’s lives (Beck, McKeown, & Kucan, 2002). Following the performance of English second/foreign language readers’ encounter with strange vocabulary; researchers have commented on the prominent role of vocabulary as an interpreter of general reading skill (Nation, 2001). Indeed, ESL/EFL readers frequently stated lack of sufficient word understanding as one of the major barriers to content comprehension so vocabulary load is a very important cue of text complexity. Likewise, Haynes and Baker (1993) concluded that the most important disadvantage for L2 readers is not the lack of reading comprehension practice, but the inadequate use of English vocabulary. To a large extent, what these studies reveal is that the threshold for reading comprehension is lexical. Lexical issues will, hence, prevent successful comprehension. Laufer (1998) and Qian’s (1999, 2002, 2004) have revealed so, by research findings on the association among vocabulary breadth/size and reading comprehension; which resulted in a fairly high relationship among them. So, in 1996, Meara proposed VLT the nearest thing we have to a standard test in vocabulary knowledge. A recent study on vocabulary size declared the prominent role of the breadth of vocabulary knowledge in performance of reading comprehension. Over two decades, researchers have depicted which breadth test of vocabulary knowledge can very well predict success in reading, writing, general proficiency, and academic achievement (Nation & Meara, 2002; Laufer & Goldstein, 2004). Likewise, Nation’s vocabulary levels test has been verified to be a useful and credible analytical tool in examining L2 learners’ vocabulary size (Qian, 1999; Read, 2000; Nation, 2001; Schmitt & Clapham, 2001; Koda, 2005) and has been widely applied by some researchers to estimate EFL/ESL learners’ vocabulary size (Zahar, Cobb, & Spada, 2001; Webb, 2005; Qian, 2008). The association among the vocabulary knowledge and reading comprehension is dynamic and difficult. The upsurge of the role of vocabulary in foreign language acquisition went hand in hand with a growing interest in vocabulary testing in second language acquisition research. Meanwhile, researchers have been able to ascertain that the breadth/size of one’s vocabulary appears to be a determining factor for second language learning (Meara, 1996). Obtaining a sufficiently large vocabulary familiarity seems to correlate strongly with other linguistic competences in the target language. Therefore, much recent work on vocabulary testing has focused on estimating how many words the learners know in their L2 (Laufer, 2003). To accomplish this goal, vocabulary breadth/size tests have been developed. These are assumed on the belief that the learners require a particular rate of vocabulary in order to be able to play in the target language, independently (Alderson & Banerjee, 2001). On the other hand, The International English Language Testing System (IELTS) is an international standardized test for assessment of English language proficiency. IELTS was established in 1989, and is jointly administered by University of Cambridge ESOL Examinations, the British Council, and IDP Education Pty Ltd. In 2007, IELTS was investigated further over a million candidates in a single 12 months period for the first time ever, making it the world’s most accepted English language test for higher immigration and education. Moreover, interest in the association of vocabulary knowledge and reading comprehension has a lengthy history in the research of second/foreign language reading. Consequently, lexical issues have prevented successful comprehension. The current study intended to examine the association between the breadth/size of vocabulary knowledge and EFL reading comprehension performance uses subtests of VLT and IELTS. Vocabulary Levels Test & Reading Comprehension A recent study on vocabulary size declared the prominent role of the breadth of vocabulary knowledge in performance of reading comprehension. Over two decades, researchers have depicted which breadth test of vocabulary knowledge can very well predict success in reading, writing, general proficiency, and