Capturing chronological variation in L2 speech through lexical measurements and regression analysis

This study aims to bridge gaps in current research by analyzing a longitudinal spoken learner corpus of low-proficiency English learners. We investigated the chronological variation in lexical measurements in second language (L2) speaking production, focusing on data from 104 low-proficiency learners elicited eight times over 23 months. Our findings show that measures such as the number of different words and type-token ratio are effective indicators of L2 speaking development, whereas the use of sophisticated vocabulary was not significantly correlated with learning duration. These results suggest that in the early stages of L2 acquisition, speaking skills are influenced primarily by lexical variation. This finding underscores the importance of lexical variation as a key factor in novice-level L2 speaking proficiency.