A study of interlanguage English intonation in Thai learners, and the degree of intelligibility and comprehensibility in native speakers' judgements

Abstract

English intonation is central to communication and has a great impact on the listener’s perception in terms of intelligibility and comprehensibility. Intonation is a problematic area for L2 learners, especially for L1 speakers of tone languages. However, intonation has been receiving attention in a very small proportion of lessons in Thai pronunciation classes. This study investigated the productions of the English intonation of Thai learners and the perceptions of native speakers of English for intelligibility and comprehensibility. There were two main experiments: the production study and the perception study. The data for the production study were collected from two groups of learners selected by the English Language Experience Questionnaire: 1) those with high language experience (n = 15) and 2) those with low language experience (n =15). They performed three production tasks: passage reading, dialogue reading and spontaneous speech to elicit tonality, tonicity and tune patterns. Native speakers of British English (n =3) served as a control group for comparison purposes. Three learners from each group were drawn by stratified sampling to read nine test sentences. With respect to the perception study, two groups of native speakers of British English with different amounts of contact to Thai learners were recruited to be the judges. The first group (n = 5) had a minimum of three years of experience teaching Thai learners whereas the second group (n =5) were teacher trainees who had minimal experience with Thai learners. The speech stimuli for the intelligibility dimension were sentence reading from the intelligibility test. The speech recordings from passage reading were used for the comprehensibility dimension. This study provides insights into the features that inhibit intelligibility and comprehensibility. The findings contribute to pedagogical issues of pronunciation teachers to prioritising the aspects of intonation to be dealt with in their syllabuses. The overall findings revealed that the Thai learners with high language experience had more similar tonality, tonicity and tune patterns to those of native speakers. On the other hand, the productions of the Thai learners with low experience contained more deviated patterns. The findings from the intelligibility dimension indicated that the experienced judges had more correct interpretations for both groups of learners than the judges with less experience did. The Thai learners with high experience obtained a higher percentage of correct perceptions from both groups of judges. The comprehensibility ratings for the learners with high experience were significantly higher from both groups of judges, and the judges with extensive experience found their speech easier to understand. Furthermore, the intonation scores from the production study showed a positive correlation with the degree of intelligibility (r = .784) and comprehensibility (r = .628), but the statistical analysis was only significant at the 0.01 level for comprehensibility.