Working Memory And L2 Speaking: The Moderating Role Of L2 Proficiency And Task Type

Task-Based Language Teaching(TBLT)has been regarded as a crucial issue in the research of second language acquisition(SLA)and a large number of efforts have been devoted to investigations exploring how task type influences language performance from cognitive perspective.Working memory(WM),as one of the central cognitive variables,has been posited as an essential role for SLA as working memory capacity(WMC)is responsible for individual differences in regulating attention resources.Due to the complex cognitive nature of L2 speech production,WM has been assumed to be an influential factor in the L2 speech process,and many studies have found evidence for the positive role of WM in L2 speech production.However,it is still challenging to reach a firm and established conclusion concerning the role of WM in L2 speech production due to the mixed results found in other investigations.The complex role of WM in L2 performance could be caused by other moderating factors,such as learners’ L2proficiency(Wen et al.,2015)and task type.The present study aims to fill this gap through investigating the effects of WM on Chinese English as a Foreign Language(EFL)learners’ second language(L2)speech production in three narrative tasks differing in cognitive difficulty and whether such results depend on learners’ L2 proficiency level.The purpose of this study is two-fold.The prime goal is to explore the relationship between WM and L2 speech production in different narrative tasks;the second goal is to examine whether the relationship would be moderated by learners’ L2 proficiency level.The participants were eighty-nine EFL learners at different levels of L2 proficiency.Participants’ WMC was assessed by means of the speaking span test(Daneman,1991)in their native language(Chinese),and L2 speech production was elicited by means of three narrative tasks: Elicited Imitation Task,Independent Speaking Task,and Picture Narration Task.Three aspects of speech production were assessed,including complexity,accuracy,and fluency.There are several significant findings yielded in the present study.Firstly,it was found that WMC,as measured by the speaking span test in participants’ L1,correlates significantly with fluency in Picture Narration Task.Secondly,the relationship between WM and L2 speech production varies in different types of tasks which differ in the way cognitive load was placed on participants and WM played a more prominent role in L2 speech production when performing tasks with higher cognitive demands in formulating and articulating stage.Thirdly,L2 proficiency significantly moderates the effect of WMC on some dimensions of fluency;specifically,WMC plays a more prominent role in the fluency dimension of L2 speech production at higher levels of L2 knowledge.The current study testifies the crucial role of WM in L2 speech production and the different roles that working memory plays in tasks with different cognitive loads.Meanwhile,the study also suggests that WM plays a more prominent role in the fluency dimension of L2 speech production at higher levels of L2 knowledge,which provides more empirical evidence for the previous debate on the moderating role of L2 proficiency.In addition,this study provides values for the design of oral tasks in language learning and teaching.Teachers should consider the cognitive load of tasks and learners’ language proficiency when implementing task-based teaching.