Receptive vocabulary size and its relationship to EFL language skills

This study analyses the relationship between receptive vocabulary size in upper-intermediate/advanced learners and EFL proficiency and the skills of reading, writing, listening and speaking. Little research has been conducted on this dimension of lexical knowledge and the four skills (Staehr, 2008; Milton et al., 2010), in spite of the fact that previous studies of separate language skills have highlighted the importance of vocabulary size for language proficiency development. A sample of 42 participants was assessed by means of a receptive vocabulary size test on ten word-frequency levels (1k to 10k), and on both receptive and productive skills (oral and written). Results reveal that vocabulary size explains language proficiency to a large extent, even in learners with vocabularies of more than 5,000 words, though its influence on performance is not as strong as in learners with smaller vocabularies. At a high proficiency level, vocabulary size is closely linked to writing and is moderately correlated with reading, speaking and listening. The findings help to provide a more complete picture than earlier research by including more proficient learners in EFL settings.