Frequency effects and second language lexical acquisition Word types, word tokens, and word production

Frequency effects in an L1 and L2 longitudinal corpus were investigated using Zipfian distribution analyses and linear curve estimations. The results demonstrated that the NS lexical input exhibited Zipfian distributions, but that the L2 lexical output did not match the NS Zipfian patterns. Word frequency analyses indicated that NS interlocutors modify their lexicon such that frequency scores decrease as a function of time that L2 learners have studied English. In contrast, the word frequency scores for the L2 output increased as a function of time. Post-hoc analyses indicated that differences in frequency scores between NS input and L2 output were best explained by the repetition of infrequent words, but not frequent words by L2 learners in the early stages of language acquisition. The results question absolute frequency interpretations of lexical acquisition for L2 learners and provide evidence for usage-based approaches for language learning.