A Study On The Development And Interaction Of Lexical Complexity And Syntactic Complexity In L2 Argumentative Writing:a Complex Dynamic Systems Approach

Researchers adopting a Complex Dynamic Systems(CDS)approach on language learning and use view second language development(SLD)as a dynamic,non-linear process with co-adaptive subsystems.A large body of studies have been conducted to examine the development of lexical and syntactic complexity,which has been recognized as important constructs in second language(L2)writing teaching and research;nevertheless,not much effort has been made to explore the developmental pattern and interactions of these two dimensions among EFL learners with different proficiency levels from a CDS perspective.The present study is aimed at describing patterns of L2 writing development in terms of lexical and syntactic complexity from a complex dynamic systems perspective,and revealing the interactions of the two subsystems.This study was based on an Argumentative Writing Course at a prestigious university in Jiangsu Province.An intact class of 22 English majors participated in the research.Students were assigned to write five three-draft argumentative essays in a semester,receiving peer feedback after Text 1 and teacher feedback after Text 2.The development of lexical and syntactic complexity for the whole class was first reported,followed by a further analysis of six carefully-selected participants,which helped reveal the proficiency-related developmental differences as well as interactional patterns.The six participants(all pseudonyms)were : L,F(intermediate-high level),J,S(intermediate level),and W,Y(lower intermediate level).Three lexical complexity measures were G,CWR,and AG,gauging lexical diversity,richness,and sophistication respectively;three syntactic complexity measures were MLTU,DC/T and CN/T,measuring sentential,clausal,and phrasal complexity respectively.The indices of lexical and syntactic complexity in each draft were first calculated by automatic computational tools.Then a series of CDS techniques,i.e.smoothing polynomial trendline,moving min-max graph,change-point analysis and moving correlation,were employed to reveal thedevelopmental trajectories of each subsystem and the interactional patterns among the subsystems.Besides,qualitative analysis based on their writings,self-reflections and interviews were also conducted to further explore the influencing factors in the developmental process.The study has yielded the following major findings:1)The developmental trajectories of lexical and syntactic complexity for the whole group are characterized by non-linearity;the three subsystems of lexical complexity reveal gradual improvement;among the three subsystems of syntactic complexity,sentential complexity and clausal complexity show obvious regression,while phrasal complexity fluctuates wildly over time.2)The developmental patterns of lexical and syntactic complexity in the six participants' writings undergo significant phase transitions,which are closely related to the influencing factors such as feedback,topic familiarity and motivation.With regard to lexical complexity,the participants at lower intermediate level show greater variability than the other four participants;with regard to syntactic complexity,the participants at intermediate level exhibit greater variability than the other participants.3)The interactional patterns among the subsystems of the two complexity dimensions change dynamically over time.For participants with intermediate-high level,there is a competitive interaction between lexical sophistication and clausal complexity,and between lexical richness and sentential complexity,but a supportive interaction between lexical diversity and phrasal complexity;for participants with intermediate level,there is a competitive interaction between lexical sophistication and clausal complexity,but a supportive interaction between lexical richness and sentential complexity,and between lexical diversity and phrasal complexity;for participants with lower intermediate level,there is a competitive interaction between lexical sophistication and clausal complexity,and between lexical diversity and phrasal complexity,but a supportive interaction between lexical richness and sentential complexity.The findings provide important methodological and pedagogical implications for L2 writing research and pedagogy.For L2 writing researchers,a CDS perspective hasits advantages in unveiling the developmental trajectories and interactional patterns of various dimensions of L2 writing.Besides,L2 writing teachers are advised to provide students with timely teaching intervention in various ways so that their lexical and syntactic complexity in L2 writing can develop at an optimal level.