Syaifullah, Syaifullah, Yulia Qoirum, Refika Andriani, and Herlinawati Herlinawati. “Using the Color Vowel Chart in Teaching Speaking”. ELT-Lectura 9, no. 2 (July 26, 2022): 136-150. Accessed July 25, 2024. https://journal.unilak.ac.id/index.php/ELT-Lectura/article/view/10317.