Built upon the Contrastive Interlanguage Analysis (CIA) framework, this corpus-based research analyzes three lexical features (lexical diversity, lexical sophistication, and cohesion) in native and nonnative English writers' academic writing and examines the potential differences in lexical performance 1) between native and nonnative English writers and 2) across all writers from various language backgrounds. The differences in lexical performance in academic writing between native and nonnative English writers and the unique characteristics of writers from different language backgrounds suggest the necessity of targeted academic writing instruction based upon learner needs. Using text length as the covariate, two Multivariate Analysis of Covariate (MANCOVA) were conducted with language background as the Independent Variable and the three lexical features as the Dependent Variables. The results revealed that nonnative English writers demonstrated significantly lower performance in lexical sophistication than did native English writers. In terms of the comparison between writers from different language backgrounds, the results suggested statistically significant differences in all three aspects of lexical features. Pedagogical implications for vocabulary instruction in academic writing for nonnative English writers include emphasizing the mastery of academic, low-frequency, and discipline-specific vocabulary. In addition, improving nonnative writers' vocabulary size and lexical diversity can offer these learners more options to build cohesion in academic writing at a deeper level. Moreover, the results of this study highlight the wide but often under-considered variability within any language group as individual learner differences come into play, thereby downplaying the idea that writers of any given language tend to perform homogenously. Instructors should acknowledge the unique writing characteristics of different nonnative writers and their varied learner needs. Thus, targeted instruction is essential to provide effective enhancement to nonnative English writers' lexical performance in academic writing.


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Graduation Date





Folse, Keith


Doctor of Philosophy (Ph.D.)


College of Education and Human Performance

Degree Program

Education; Teaching English to Speakers of Other Languages









Release Date

August 2019

Length of Campus-only Access

1 year

Access Status

Doctoral Dissertation (Open Access)