Telaumbanua, Mentari Selfi Yanti, Tiara Kristina Pasaribu, and Jubil Ezer Sihite. “The Differences Between American and British Diphthong: A Case Study of Joe Biden and Boris Johnson”. Jurnal Pendidikan dan Konseling (JPDK) 4, no. 5 (October 16, 2022): 5711–5715. Accessed December 2, 2024. http://journal.universitaspahlawan.ac.id/index.php/jpdk/article/view/7579.