Breadth and Depth of Vocabulary Knowledge and Their Effects on L2 Vocabulary Profiles

Breadth and depth of vocabulary knowledge have been studied from many different perspectives, but the related literature lacks serious studies dealing with their effects on vocabulary profiles of EFL learners. In this paper, with an aim to fill this gap, the relative effects of breadth and depth of vocabulary knowledge on L2 vocabulary profiles were analysed. In the first stage of the study, learner essays (n = 84) and native essays (n = 75) were compared in terms of vocabulary profiles through the use of an online database, and each participant obtained vocabulary profile scores from four different levels. In the next stage, the learners' depth and breadth of vocabulary knowledge were measured by using two different vocabulary tests, and then the scores they obtained on these tests were hierarchically regressed on their profile scores. The results suggested that both breadth and depth of vocabulary knowledge had significant and robust effects on the L2 vocabulary profiles of the EFL learners; however, depth of vocabulary knowledge appeared to be a better predictor of vocabulary profiles than breadth of vocabulary knowledge.