Phonphanich, Siriluck H., and Somsonge Burusphat. “The Positive and Negative Effects of Tonal L1 on the Acquisition of Tonal L2: A Case of the Standard Thai Tones and the Chinese Zhuang Learners”. LEARN Journal: Language Education and Acquisition Research Network 14, no. 2 (July 20, 2021): 28–58. Accessed May 4, 2024. https://so04.tci-thaijo.org/index.php/LEARN/article/view/253260.