Usage-based approaches to language acquisition explain language development as a gradual process of generalizing constructions through language experience. This study investigated second language learners' development of constructional knowledge from the perspective of usage-based language development. A total of 169 Korean EFL students at five grade levels completed a sentence-sorting and a translation task. Results of the sorting task showed stronger constructional sorting as the learners' grade level increased. Additionally, the sorting of intermediate-level learners was influenced by verb semantics such that the sentences including light verbs were more strongly clustered according to constructions than the sentences with heavy verbs, suggesting learners' reliance on light verbs in the early stages of constructional development. Results of the translation task demonstrated a higher translation accuracy with increasing proficiency, but with a significant amount of variation across individual constructions contingent on the constructions' syntactic and semantic complexity. Overall, our findings confirm the usage-based development of L2 learning.