Research has suggested the important role of vocabulary knowledge in second language (L2) speaking proficiency. However, earlier studies tended to disregard the congruence in test format between assessing vocabulary knowledge and speaking skills with the former predominantly measured in written format. The current study measured vocabulary…

In the seven decades since Leopold's groundbreaking 1939 study, there has been no longitudinal study covering more than two years of a Japanese bilingual subject's development. Despite the lack of longitudinal research, however, we have been broadly informed by the veritable outpouring of research on a short-term basis since the late twentieth…