Typical Adult Speakers' Tongue-Palate Contact Patterns for Japanese Alveolar and Post-Alveolar Sounds

Abstract

: OBJECTIVE: More than 160 clients with articulation disorder have undergone visual feedback training using electropalatography (EPG). However, EPG data regarding typical tongue-palate contact patterns for Japanese speakers are limited. The purpose of this study was to generate EPG target patterns for the Japanese alveolar and post-alveolar consonants which were most often practised during EPG therapy. METHODS: The participants were 15 Japanese-speaking adults without present or past speech, language, or hearing problems. EPG data were recorded for [t, d, n, s, ɕ, ts ͡ , dz ͡ , tɕ ͡ , dʑ ͡ ] in vowel-consonant-vowel syllables, such as [ata]. Cumulative templates were generated from the maximum contact frame for each sound; a quantitative analysis, such as alveolar total, centre of gravity and variability index, was performed to examine the difference of each sound. RESULTS: Although tongue-palate contact proportion varied for each person, basic configurations for each sound were similar. A cumulative template, inclusive of all participants, represented target patterns that are specific for each sound. Quantitative analysis revealed distinctive characteristics of each sound. CONCLUSION: The cumulative templates and quantitative characteristics for each Japanese consonant provided valuable information for visual feedback training as