Handle it in-house? Learner corpora frequency lists and lexical sophistication

Vocabulary lists of high-frequency lexical items are an important resource in language education and a key product of corpus research. However, no single vocabulary list will be useful for every learning context, with the appropriateness of such lists affected by the corpora on which they are based. This paper investigates the impact of corpus selection on one measure of lexical sophistication, Advanced Guiraud, focusing on two frequency lists originating from an in-house learner corpus (PELIC) and a global learner corpus (Cambridge Learner Corpus). This analysis shows that frequency lists derived from both types of learner corpus can effectively serve as the basis for measuring the development of lexical sophistication, regardless of the specific program of the learners. Therefore, publicly available learner corpus frequency lists can be a reliable resource for stakeholders interested in the lexical gains of language learners.