Using CA-Informed Transcription Symbols in Conversation Teaching to Improve Thai EFL Learners’ English Stress and Intonation

This research explores the effectiveness of Conversation Analysis (CA) transcription symbols in teaching English stress and intonation, as well as students' attitudes toward their role in understanding prosody. A quasi-experimental study was conducted with 43 undergraduates enrolled in an English conversation class. Participants were divided into control and experimental groups, both receiving identical materials. Over five weeks, the experimental group was taught using CA transcription symbols, while the control group used transcripts without these visual cues. The findings indicate substantial improvement in pronunciation accuracy among students in the experimental group, while the control group demonstrated minimal progress. An independent samples t-test revealed a significant difference in post-test performance between the two groups (t = 8.37, p < .001, 95% CI [8.95, 14.65]), with a large effect size (Cohen’s d = 2.614). The experimental group’s mean scores increased significantly from 47.09 (SD = 7.56) to 66.19 (SD = 6.71), whereas the control group’s scores rose only slightly from 54.77 (SD = 8.61) to 62.06 (SD = 7.37). Qualitative data indicated that learners developed greater awareness of English stress and intonation, finding the symbols helpful in enhancing their pronunciation. The study supports integrating CA transcription symbols into English conversation teaching to enhance students' prosodic awareness and pronunciation skills.