Thai phonetically balanced word recognition test: Reliability evaluations and bias and error analysis

Abstract

Word recognition score (WRS) is one of the measuring techniques used in speech audiometry, a part of a routine audiological examination. The test’s accuracy is crucial and largely depends on the test materials. With emphasis on phonetic balance, test-retest reliability, inter-list equivalency, and symmetrical phoneme occurrence, Thammasat University Phonetically Balanced Word Lists 2014 (TU PB’14) were created with five different lists, each with 25 Thai monosyllabic words. TU PB’14 reflects Thai phoneme distribution based on large-scale written Thai corpora, InterBEST [1]. To evaluate its validity and test-retest reliability, the lists were given at five intensity levels (15–55 dB HL) in test and retest sessions to 30 normal-hearing subjects. The differences in performance between the two sessions are not significantly large and correlation coefficients at the linear regions are all positive. Analysis of listeners’ errors, including sequence recurrences, was carried out. Errors occurred predominantly in the case of initials, followed by finals and lexical tones. Confusion patterns of initials, finals, and tones are in line with those found for Thai speech sounds in noise condition. Interestingly, vowels are found to be most resistant to confusion. Finally, possible effect of lexical frequency is examined and discussed.

Phonetically balanced and psychometrically equivalent monosyllabic word lists for word recognition testing in Thai

“…The lists started out with two lists of relatively equivalent 50 monosyllabic words, which then divided into four lists of 25 words to save testing time. Even though RAMA.SD-1 and RAMA.SD-2 are commonly used in hearing clinics across Thailand, many limitations of the lists have been observed [4][5] [6]. There is a large degree of asymmetrical phoneme occurrences among the word lists (see Tables 2-5) and cases of duplicate words across different lists can be found [5][6].…”

“…TU PB'14 reflects Thai phoneme distribution [7] based on large-scale written Thai corpora, InterBEST [8]. The lists were given in test and retest sessions to 30 normal-hearing subjects to evaluate in terms of relative inter-list equivalency and test-retest reliability [5] [6]. Detailed analysis of listeners' misperceptions and confusion matrices were also analyzed revealing errors occurred predominantly in the case of initial only, final only, and initial along with final consonants [6].…”

“…Focusing on major criteria, phonetic balance, test-retest reliability, and list equivalency, Thammasat University Phonetically Balanced Word Lists 2014 (TU PB'14) were created [5] [6]. TU PB'14 reflects Thai phoneme distribution [7] based on large-scale written Thai corpora, InterBEST [8].…”