Rooted in Complex Dynamic Systems Theory, the study which is based on a learner written developmental corpus (ca. 1900 essays written by 100 learners over 3 years), indicates that intra-individual variation significantly predicts the average semester growth rates (ASGR) of most measures of complexity, accuracy, and fluency.
According to Complex Dynamic Systems Theory (CDST), language is a system which consists of internally complex subsystems which develop in different ways at various rates in a non-linear fashion, interact forming supportive, competitive or conditional relationships, and exhibit high variation which is said to be conducive to language development (Larsen-Freeman and Cameron 2008; Verspoor, de Bot and Lowie 2011). The aim of the presentation is to report the results of a longitudinal, corpus-based hybrid type of study which was conducted in 2014-2017 in one of Polish secondary schools. The study is based on a usage-based, developmental corpus which was built on the basis of repeated measurements and which consists of around 1900 essays written by 100 learners over the period of three years. The aim of the study was to investigate the phenomenon of intra-individual variation in the emergence of syntactic complexity, i.e. subordination, coordination and nominalisation, lexical complexity, i.e. lexical density, sophistication, variation and frequency, accuracy and fluency in written production at secondary school. Intra-individual variation is defined as differences in the level of a developmental variable within individuals upon repeated measurements. Emergence refers to microgenetic growth in the development of language subsystems observed systematically over a longer period of time. In general, the results of the study reveal highly variable and competitive language development in which the learners' progress in fluency as well as syntactic and lexical complexity takes place at the cost of accuracy. More specifically, the results indicate that intra-individual variability significantly predicts the average semester growth rates (ASGR) of most measures of complexity, accuracy, and fluency.
Key words: Complex Dynamic Systems Theory, intra-individual variability, average semester growth rate, complexity, accuracy, fluency, English L2 writing, secondary school
References: Larsen-Freeman, D. and L. Cameron. 2008. Complex Systems and Applied Linguistics. Oxford: Oxford University Press. Verspoor, M., K. de Bot and W. Lowie. 2011. A Dynamic Approach to Second Language Development. Amsterdam: John Benjamins Publishing Company.
