Constructing time phonetically balanced word recognition test in speech audiometry through large written corpora

Thammasat University Phonetically Balanced Word Lists 2014 (TU PB´14) are created with 5 different lists of 25 Thai monosyllabic words. TU PB´14 is constructed based on Thai phoneme distribution [1] from large-scale written Thai corpora, InterBEST [2]. The two major criteria are phonetic balance and list equivalency. Phoneme occurrences of original 5 Thai monosyllabic word lists (OTL) are also given and discussed. To evaluate reliability and inter-list equivalence of TU PB´14 and OTL lists, all 10 lists are given to 30 normal-hearing subjects to obtain discrimination scores. Discrimination scores of the five TU PB´14 tests yield a curve that is comparable with that of the OTL, but with the former being slightly lower (more difficult). Importantly, all lists of TU PB´14 exhibit relatively equal range of difficulty. To further examine variability of discrimination scores, we plan to conduct similar tests on hearing impaired subjects.