This study examined what the effects of computer discussions on interactive English language use of students who were considered reticent in class, and their perceptions of self-efficacy and language anxiety, and how different individual types of students would interact with the different contexts of oral and computer discussions. Data were collected using quantitative methods for discussion data and self-efficacy and language anxiety measures, and qualitative methods for interview and class observation from an advanced ESL writing class. The results indicated that the computer discussions seemed to help reticent students enhance their quantitative productivity in discussions, but it did not necessarily elicit more sophisticated and complex English language from these students. The analyses for students’ self-efficacy and anxiety measures further suggested that the computer discussions could contribute to lowering students’ language anxiety but not to improvement of their self-efficacy. In addition, the qualitative analysis illustrated that the students of one participant group would establish different emotional experience from those of the other group in the oral discussions. Then, the experiences of these students seemed to be created differently within the novel context of computer discussions.