A Case Study On Dynamic Development Of Syntactic Complexity And Accuracy In Non-English Majors’ L2 Writing

Syntactic complexity and accuracy are two significant constructs which have been widely used to gauge second language（L2）writing development.And the interrelationship between complexity and accuracy has been a controversial issue for a long time.Studies in the field of traditional second language acquisition（SLA）have mainly adopted a static approach to examine L2 writing through cross-sectional comparisons of group averages,with the assumption that L2 development is a linear progressive process,ignoring individual difference and variability.Dynamic systems theory（DST）has provided a novel theoretical framework and specific research methods.However,DST-based L2 writing studies have been quite limited so far.Furthermore,there are even fewer case studies which trace different proficiency learners’ L2 writing development over a relatively long period.A dynamic,process-oriented approach was adopted in this study to longitudinally trace L2 writings of three non-English majors with different initial English proficiency levels over three semesters.And altogether 66 argumentative compositions which were completed every two weeks were collected to examine the dynamic developmental characteristics of syntactic complexity and accuracy and to explore variability and interaction patterns in the process of development.Some dynamic analysis methods including growth trajectory plots,moving min-max graph,Mental Carlo simulation,change point analysis and moving correlation analysis were applied so as to reveal dynamic developmental mechanism.Besides,a semi-structured interview was also implemented with the hope to interpret main causes of variability and interconnected development of syntactic complexity and accuracy from learners’ perspective.This study attempts to resolve the following three research questions:（1）What are the developmental trajectories of syntactic complexity and accuracy in L2 writings by the three different proficiency non-English majors?（2）What are the characteristics of dynamic variability during the development of syntactic complexity and accuracy? And are there significant change points in the development of L2 writing?（3）How do syntactic complexity and accuracy interact in the process of L2 writing development?Research findings indicate that:（1）There are great distinctiveness among dynamic developmental trajectories of different measures of syntactic complexity and accuracy in L2 writings by different proficiency L2 learners,in which non-linearity,unpredictability and individual variation are characterized.However,three participants are similar in the ascending developmental tendency of complex nominal phrase（CN/C）and a lack of significant development of mean T-unit length（MLT）.Therefore,syntactic complexity and accuracy development in individual learners possess characteristics of regularity as well as inter-individual variation.（2）According to variability analysis,the advanced learner shows no significant change in both syntactic complexity and accuracy.Her L2 writing development reaches a state of dynamic stability at the plateau period.The upper-intermediate learner shows moderate development,with a small degree of variability in syntactic complexity development and a significant developmental stage transition in accuracy.The intermediate learner achieves significant developmental stage transition in all four measures of syntactic complexity and accuracy.At a state of dynamic instability typical of dynamic systems,she shows the greatest developmental potential and progressive space.The research findings indicate that initial proficiency is an important factor of L2 developmental characteristic.Besides,interview analysis finds various factors including topic familiarity,motivation,attitude and learning experience also have explanatory power for individual developmental variability.（3）There are dynamic interactive effects between different measures of syntactic complexity and accuracy.The advanced learner shows supportive interaction in the development of CN/C and ratio of error-free T-units（EFT/T）and the two measures achieve dynamic equilibrium in development.For the upper-intermediate learner,syntactic complexity and accuracy development have not reached dynamic equilibrium,displaying alternating competitive and supportive interactions.For the intermediate learner,the dynamic interaction between CN/C and EFT/T shifts from competitive state to supportive state,which is related to her increasing language proficiency.Therefore,the dynamic interactional patterns between syntactic complexity and accuracy are characterized by individual variation and unpredictability.This study is of great significance in revealing the underlying developmental mechanism of L2 learners’ written language.Besides,the applicability and superiority of DST and its unique variability analysis methods to L2 writing research are verified.Meanwhile,this study will provide important pedagogical implications for L2 writing teaching.Lastly,limitations of this study and prospects for future research are proposed.