Dynamism of collocation in L2 English writing: A bigram-based study

Here we present a longitudinal study of collocation, highlighting bigram development in L2 writing over a five-month span. Our analysis is primarily based on the learner corpus, a collection of 570 untimed L2 writing which is benchmarked against a reference corpus, the BNC. We applied two measures, the mean MI and the average t, computed from the learner corpus, to quantify both overall performance and individual variation. Interviews with three learners were conducted to explore factors contributing to the dynamism of bigram development. Our study found that, across the five times of writing, (1) learners' command of bigrams, those of high quality in particular, is fairly unstable; (2) inter- and intra- individual variations account for the individual differences in managing bigrams over time; and (3) learners' perception of collocation and their allocation of resources add to the dynamism of bigram development. Our study implies that teaching collocation from a dynamic perspective deserves increased attention. It is advisable to consider individual differences when allocating resources in teaching collocation.