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 well as EPG assessment.

Electropalatography (EPG) activities in Japan and the impact of the COVID‐19 pandemic on EPG research and therapy: A report of presentations at the 7th EPG Symposium

“…Initially, EPG research focused on reporting typical tongue palate contact patterns for Japanese speakers in order to provide EPG target patterns for use as visual feedback in speech therapy (see Appendix A in the additional supporting information). This is because the EPG data published in the 1980s were based on the EPG plate of the Rion system, which is different from the current Mcyam EPG plate in the number and placement of electrodes (Fujiwara & Yamamoto, 2020;Fujiwara et al, 2008). Recent EPG studies carried out in Japan have covered a wide range of topics, but most of them focused on articulation errors associated with cleft palate, followed by those related to skeletal malocclusion, and hearing impairment (see Appendix A online).…”