KnowlesM. S.HoltonE. F.RobinsonP. A.CaraccioliC. (2025). The adult learner: The definitive classic in adult education and human resource development (10th ed.). Taylor & Francis Ltd. https://doi.org/10.4324/9781003387671
4.
Macmillan Education ELT. (2010, July 27). David crystal - Is control of English shifting away from British and American native speakers?[Video]. YouTube. https://youtu.be/YJ29zDW9gLI?si=V0ukbxtfLM2CBrtv
5.
MoyerA. (1999). Ultimate attainment in L2 phonology: The critical factors of age, motivation, and instruction. Studies in Second Language Acquisition, 21(1), 81–108. https://doi.org/10.1017/s0272263199001035