Native Speakers and Task Performance: Comparing Effects on Complexity, Fluency, and Lexical Diversity

This article argues that a native‐speaker baseline is a neglected dimension of studies into second language (L2) performance. If we investigate how learners perform language tasks, we should distinguish what performance features are due to their processing an L2 and which are due to their performing a particular task. Having defined what we mean by “native speaker,” we present the background to a research study into task features on nonnative task performance, designed to include native‐speaker data as a baseline for interpreting nonnative‐speaker performance. The nonnative results, published in this journal ( Tavakoli & Foster, 2008 ) are recapitulated and then the native‐speaker results are presented and discussed in the light of them. The study is guided by the assumption that limited attentional resources impact on L2 performance and explores how narrative design features—namely complexity of storyline and tightness of narrative structure—affect complexity, fluency, accuracy, and lexical diversity in language. The results show that both native and nonnative speakers are prompted by storyline complexity to use more subordinated language, but narrative structure had different effects on native and nonnative fluency. The learners, who were based in either London or Tehran, did not differ in their performance when compared to each other, except in lexical diversity, where the learners in London were close to native‐speaker levels. The implications of the results for the applicability of Levelt's model of speaking to an L2 are discussed, as is the potential for further L2 research using native speakers as a baseline.