Phonphanich, Siriluck H., and Somsonge Burusphat. 2021. “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 (2):28-58. https://so04.tci-thaijo.org/index.php/LEARN/article/view/253260.