Reconsidering the syntactic complexity measures on L2 spoken English: A multi-dimensional perspective.

Based on a review of previous measures employed in English syntactic complexity investigation, this article, following Biber's Multi-dimensional approach, re-establishes a comprehensive new measure system which is composed of four dimensions i.e. Subordination, Length of Production, Coordination and Nominals using factor analysis upon a collection of indices in reference. Under the newly established framework, the research examines the effects of grade level and genre factors on second language English learners' syntactic complexity in oral English in terms of the four indices representing the four dimensions. ANOVA results show that all indices except C/T, the one representing the Subordination dimension, which shows stability across grade levels, are positively related with grade level and susceptible to genre. In the argumentative genre, students generally produce more complex sentences than in the narrative genre as regards all the four dimensions.