A Study On The Lexical Richness Of Argumentative Writing By Chinese Doctoral Students

It is well acknowledged that lexical use plays an essential role in second language writing.Efforts on lexical selection are needed when a writer strives for a high-quality writing.Therefore,lexical richness has caught researcher's attention for a long time and studies on this topic can be found in large quantity;however,few people have conducted any studies to investigate the features of lexical richness in doctoral students' writings or detected the relationship between indices of lexical richness and overall writing quality.With the assistance of automatic tools for calculating data,this study collected and analyzed the argumentative writings by 60 doctoral students from over 20 departments in a comprehensive university.Each essay was processed in terms of altogether 14 indices of lexical richness and their corresponding results were used to make more complicated comparisons.This study has yielded the following findings:1.Doctoral students' lexical usage generally achieved intermediate-high or even high level.Among the 14 indices,these participants showed advantages when it came to lexical density and lexical diversity.Also,the fluctuation of the 60 frequency values was the biggest among the 12 indices of lexical sophistication.2.With regard to the relationship between indices of lexical richness and overall writing quality,trigram and AWL were proven to be highly correlated with writing quality.Meanwhile,significant correlation was found in both AoA and Range.Nevertheless,the left 10 indices were not able to discriminate the writing quality.3.The two groups(high achiever group vs.low achiever group)showed significant differences in terms of n-gram and AWL(i.e.,high achievers used less n-grams but more academic language in their essays than low achievers did),while other indices did not show significant differences.The findings of this study have both theoretical and pedagogical implications.Theoretically,this study can revise and build a new framework for lexical richness research and facilitate the development of research on the relationship between lexical richness and writing quality.Pedagogically,teachers may encourage students to pay more attention to indices that have significant correlation with writing quality,like words from AWL and different ranges.Meanwhile,students should raise their own awareness of using these words.Besides,post-graduate-level language learners should keep strengthening lexical learning so as to overcome the "plateau period" and reach a higher level.