Development of a Thai phonetically balanced monosyllabic word recognition test: Derivation of phoneme distribution, word list construction, and response evaluations

• Published in: Speech communication 2018-10, Vol.103, p.1-10
• Main Authors: Tantibundhit, Charturong, Onsuwan, Chutamanee, Munthuli, Adirek, Sirimujalin, Ploypailin, Anansiripinyo, Thanaporn, Phuechpanpaisal, Sutanya, Wright, Nida, Kosawat, Krit
• Format: Article
• Language: English
• Subjects: Equivalence; Error analysis; Familiarity; Homogeneity; Intelligibility; Language tests; Large-scale written Thai corpus; Perceptions; Perceptual errors; Phonemes; Phonetically balanced word lists; Phonetics; Psychometric function; Recognition; Reliability analysis; Speech; Speech audiometry; Test validity and reliability; Thai language; TU PB’14; Word lists; Word recognition
• ISSN: 0167-6393; 1872-7182
• DOI: 10.1016/j.specom.2018.07.004

•1st Thai PB lists with phoneme balance, familiarity, list-equivalency, homogeneity.•Derivation of phoneme distributions from biggest large-scale written Thai corpora.•Selection and construction of 5 lists of 25 words based on optimization approach.•Evaluations using test-retest discrimination scores, confusion matrices, errors.•No χ2 significant results of psychometric functions on slope/intercept of 5 lists. This paper proposes a test tool for Thai word recognition, the Thammasat University Phonetically Balanced Word List 2014 (TU PB’14), standardized on several major criteria: phonemic balance, familiarity, reliability, list equivalency, and homogeneity. Phoneme distributions from the largest written Thai corpus (InterBEST) were obtained and used to construct five phonetically balanced word lists, each containing 25 frequently occurring monosyllabic words. Listeners’ percent correct discrimination scores from test and re-test sessions were not significantly different, confirming test reliability. Detailed analysis of listeners’ errors revealed that perceptual errors occurred predominantly for initial sound only, final only, and initial together with final. In terms of list equivalency and homogeneity, derived psychometric function slopes of TU PB’14 ranged from 0.0941 to 0.1155, while intensities required for 50% intelligibility ranged from 41.0279 to 41.3697. Two-way Chi-Square analysis performed on both parameters indicated that there was no significant difference among the word lists.