ABSTRACT
This chapter focuses on the ways that productive lexical knowledge has been investigated using learner corpora. A majority of lexis-focused learner corpus studies have been cross-sectional in nature, likely due to the relative ease of collecting large amounts of data in a relatively short period of time. Many learner corpus studies related to lexical diversity and lexical sophistication have at least implicitly treated lexical development as a unidimensional phenomenon. Treating the construct of lexical sophistication as multivariate has also contributed to our understanding of development and proficiency differences. Reference corpus word frequency is the most common method of estimating the sophistication of a particular word. Generally, cross-sectional studies have indicated that more proficient Second Language (L2) learners tend to use a wider variety of words and words that are more sophisticated. Longitudinal studies investigate the changes that occur in individuals’ L2 lexical use in writing and/or speaking over a period of time.
