the link between breadth and depth of vocabulary knowledge regarding reading comprehension performance; related literature

Reading has been and is a demanding task for foreign language learners. correspondingly, vocabulary knowledge plays an extremely vital role in foreign language learning and numerous researchers have investigated the correlation between vocabulary knowledge and reading comprehension. however, research on breadth and depth of efl learners’ vocabulary knowledge and their mutual interactions is inadequate. accordingly, the present paper intends to review the relationships between efl students’ vocabulary knowledge and reading comprehension and analyze whether breadth and depth of vocabulary knowledge are correlated to each other. having reviewed numerous studies in this regard, it was found that whereas both breadth and depth vocabulary knowledge have vital roles in efl learners' reading comprehension performance, depth of vocabulary knowledge plays a more significant role. it was also found that depth and breadth of vocabulary knowledge are positively correlated, that is, those learners who had students with large vocabulary size will have a deeper knowledge of the words, too.