Developmental style in second language processing: A study of inter-learner variation in the acquisition of English as a second language

Research into how learners acquire second language has established that there are developmental stages but has not established the nature of variation within these stages. On the basis of a longitudinal study of the speech of six learners acquiring English as a Second Language (ESL), this thesis investigates the proposals which have been made about variation in stages within the paradigm established by the Multidimensional Model (MDM). Of particular interest is the variational option hypothesis in Processability Theory (PT), the theoretical framework of this thesis. The findings indicate that these variational options and the variational features are not satisfactory in three main respects. They are based on a theoretical construct which makes problematic assumptions about the learner's knowledge of the second language, they do not reliably predict variation and they exclude important aspects of variation. This thesis proposes a new approach termed 'developmental style' which suggests that learner orientation at each stage can be defined in terms of a learner's lexical or grammatical orientation. The findings demonstrate support for the developmental hypothesis and show that learners are consistent in their particular developmental style at the different stages investigated. The results indicate that learners vary in terms of their general grammatical development at any stage. This study also finds that language background gender and task are variables which need to be controlled (informally) in order to demonstrate developmental styles.