The lexical sophistication of second language learners’ academic essays

Abstract

This report presents a validation of an updated version of Laufer and Nation’s (1995) lexical frequency profile (LFP). A measure of free productive vocabulary that uses a computer program to compare essays with wordlists, informing about the sophistication of vocabulary within texts. The main adaptation to this measure is the use of alternative word lists as benchmarks. To assess concurrent validity, the profiles of essays written by 472 advanced second language learners (using both traditional and recently compiled wordlists) were correlated with a range of language proficiency tests. Unlike previous studies, longer essays (2000 words in length) written in an authentic environment were used to validate the LFP. The general findings were that the ratios generated from both sets of word lists correlated significantly with the measure of written proficiency. Although not strong, the correlations were consistent with previous studies and indicated that students who received low scores for writing relied on high-frequency words (and vice versa). However, the new word lists yielded weaker correlations. The study concludes that although the ratios of vocabulary types show a reliable tendency, they do not correlate strongly enough to be used as independent predictors of proficiency.