Thesis(Ph.D.)--Chulalongkorn University, 2009

The objectives of this study were to examine the effects of language ability levels and types of communication strategies (CSs) on students’ oral communication ability, in both main and interaction effects, and to explore the differences in the use of the CSs by high and low language ability students. The subjects in the study were 100 third-year English majored students enrolled in the speaking course in the Faculty of Humanities at the University of the Thai Chamber of Commerce (UTCC). They were categorized into two groups, high and low ability, based on their average grades of their previous three English courses. The subjects participating in the main study were randomly selected for data analysis purposes. Research instruments were the Oral Communication Test (OCT), and the Strategies Used in Speaking Task Inventory (SUSTI). The research design was the ‘randomized block design’. Descriptive statistics, 2x2 ANOVA, and t-test were used to analyze the quantitative data, and the content analysis was used to analyze the qualitative one, and to confirm the results obtained from the quantitative analysis. It was found that language ability levels and types of CSs used had the significant effects on the students’ oral communication ability. In addition to this, no significant interaction effect between them was found. The developed OCT could differentiate the high language ability students from the low language ability ones. Moreover, it was found that the students who employed risk-taking strategies performed significantly better in oral communication than those applying risk-avoidance strategies. The content analysis illustrated that the high ability students preferred risk-taking strategies such as social-affective, fluency-oriented, help-seeking, and circumlocution strategies, whereas the low ability students tended to employ more risk-avoidance strategies like time-gaining strategies.