| Lexicon is not only the foundation of language learning,but also a prerequisite for language use.Therefore,lexical acquisition has attracted much attention in the research on second language acquisition.At present,studies on second language(L2)lexical acquisition explore the development of lexical acquisition from the facets of lexical knowledge or lexical use,which finds that developmental paths of lexical knowledge and lexical use are non-linear and dynamic.Such finding coincides with the view of Dynamic Systems Theory(DST)on language.From the perspective of DST,lexical acquisition is a complex and dynamic system,which consists of two interconnected sub-systems,lexical knowledge and lexical use.Its development,under the influence of multiple factors,is a non-linear process.Additionally,due to multiple factors,the two interconnected sub-systems show different interactional characteristics.However,few studies have combined the development and interaction of lexical knowledge and lexical use within the framework of DST.Therefore,the current study,based on the Dynamic Systems Theory,aims to describe the development and interactional characteristics of lexical knowledge and lexical use in the context of English as a foreign language(EFL).Lexical knowledge is measured through the dimensions of breadth and depth of lexical knowledge,while lexical use is measured by the dimensions of lexical sophistication and lexical variation in argumentative writing.More importantly,the current study also endeavors to reveal the influential factors underlying the development and interactional characteristics of lexical knowledge and lexical use.Participants of the current study are 15 students from a university of 211 Project in Jiangsu Province.They are third-year English majors from the same class and have been receiving formal English education for about 12 years when participating in this study.In the academic year,15 participants receive six tests on breadth of lexical knowledge,six tests on depth of lexical knowledge,and six argumentative writing tasks.The Vocabulary Levels Test designed by Schmitt et al.(2001)is adopted to test breadth of lexical knowledge,The Depth of Vocabulary Knowledge Test designed by Qian et al.(2004)is employed to test depth of lexical knowledge,and the argumentative writing tasks are used to obtain the values of lexical sophistication and lexical variation.Argumentative writing tasks are completed after class.On the completion of an essay,the researcher submits the electronic version of participants’ compositions to a website developed by Ai&Lu(2010),which automatically analyzes and generates the values of lexical sophistication and lexical variation.Values of breadth and depth of lexical knowledge,lexical sophistication and lexical variation are quantitatively analyzed by DST techniques,trying to describe the development and interactional characteristics.Qualitative analysis of the data from semi-structured interviews is conducted to explore the factors that influence the development and interactional characteristics.The major findings of the current study are as follows:(1)In terms of the development of lexical knowledge,breadth and depth of lexical knowledge experience a rise in the academic year on the group level.On the individual level,developmental paths of both breadth and depth of lexical knowledge show inter-individual variability.Individual developmental trajectories are featured by both progression and regression,reflecting non-linear characteristics.In addition,stagnation exists in the developmental paths of breadth and depth of lexical knowledge at the end of the academic year.Finally,individual’s motivation in lexical knowledge learning is an interfering factor underlying the development of lexical knowledge.(2)Development of lexical use is more complex than that of lexical knowledge.Developmental trajectories of two dimensions,namely,lexical sophistication and lexical variation,are non-linear on both the group level and the individual level.Besides,the two dimensions also show inter-individual variability on the individual level.What’s more,inter-individual variability is greater in lexical sophistication than in lexical variation and is influenced by individual’s writing motivation.(3)The interactional characteristics of the four dimensions are rather diverse on both group and individual level.On the group level,the interaction between breadth and depth of lexical knowledge is competitive,while the interactions of the other five pairs are asymmetric,namely,change between competitive and supportive.On the individual level,the interaction between lexical knowledge and lexical use is more complex than that between the internal dimensions of lexical knowledge and lexical use.In the interaction between lexical knowledge and lexical use,the majority is asymmetric,while in the interaction between the internal dimensions of lexical knowledge and lexical use,the majority shows a single competitive or supportive relationship.Additionally,individual’s strategy for lexical knowledge learning and motivation in writing exert an influence on the interactional characteristics of four dimensions.Findings of the current study can be used for reference in research on lexical acquisition and classroom teaching.In terms of research on lexical acquisition,this study provides researchers with a dynamic approach and corresponding qualitative analyses when focusing on complex and dynamic lexical systems.Meanwhile,this study is also considered a stimulus for researchers to take into account the receptive and productive facets of lexical acquisition when researching on lexicon.In terms of classroom teaching,this study enables teachers to pay close attention to lexical knowledge in writing teaching and assessment,and to ensure that students understand the interaction between lexical knowledge and lexical use. |
