Abstract
The present study attempts to examine the developmental processes of two types of speaking ability of Japanese EFL learners by analyzing the breadth and depth of conjunction use in oral performance. Based on Cummins' Hypothesis (1980), the author (2004) generated a research hypothesis focusing on the commonalities and dissimilarities between the two types, including BICS-type speaking and CALP-type speaking, and tested it by four studies (2005a, 2006a). From a cognitive linguistic perspective, the interlanguage corpus data gathered through the performance tests enabled the author to examine the internal process of linguistic production and information processing by inspecting the participants' use of conjunctions. Hierarchical cluster analysis with two explanatory variables yielded different types of grouping between the two types of oral performance. Accordingly, it was found that the two types of speaking ability were acquired through different developmental stages.
