Intra-individual Variability in the Emergence of Lexical Complexity in Speaking English at Secondary School

Abstract

Complex Dynamic Systems Theory (CDST) focuses on second language development (SLD) as opposed to second language acquisition (SLA). Emphasising internal complexity of the language system as well as dynamic and non-linear nature of language development, it represents a new approach to the role of variability which is rooted in developmental psychology. This approach agrees with research findings from the 1980s which identified different types and causes of variability, but it treats variability as the main factor responsible for language development and not as a peripheral phenomenon. Intra-individual variability, defined as differences in the level of a developmental variable within individuals and between repeated measurements, is said to have a positive influence on language development at various levels of proficiency. The present paper describes the third part of the case study whose aim is to analyse intra-individual variability in the emergence of lexical complexity in speaking English as a foreign language at secondary school in the case of a good, average and poor language learner. The first part of the case study examined this phenomenon with respect to general measures of complexity, accuracy and fluency, whereas the second part–with respect to specific measures of syntactic complexity. The results of the third part of the case study show some significant differences between the learners in terms of lexical variation as opposed to density, sophistication and frequency but hardly any such differences in intra-individual variability, pointing at the same time to a weak positive relationship between this type of variability and the rate of development.