Trakantalerngsak, Tanporn. “The Introduction of Nihongo Speech Trainer: A Tool for Learning Japanese Sounds”. NIDA Journal of Language and Communication 24, no. 35 (July 10, 2019): 48–58. accessed August 28, 2026. https://so04.tci-thaijo.org/index.php/NJLC/article/view/202423.