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. the relationship between two dimensions of vocabulary knowledge, that is, breadth of vocabulary (the number of words known) and depth of vocabulary (the richness of word knowledge), and their effects on different aspects of english reading in students learning english as a second language is the main objective in this study. 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. they both contributed to word reading, but breadth of vocabulary had a stronger effect than depth of vocabulary. when reading comprehension was the outcome measure, vocabulary breadth significantly predicted a multiple-choice reading comprehension measure, which requires general understanding of the text, while vocabulary depth contributed to summary writing, a measure of deeper text processing.