“…However, implementation of English as the language of instruction might not be successful because instructors and students may be less than proficient in English (Doiz, Lasagabaster, & Sierra, 2013;Macaro et al, 2018). Studies from a variety of non-English speaking countries consistently have documented the challenges students and instructors experience when instruction is delivered in English (Bolton, Botha, & Bacon-Shone, 2017;Bradford, 2016;Hu & Lei, 2014;Nguyen, Hamid, & Moni, 2016). Yet, we lack reliable evidence about whether these self-reported challenges translate into actual negative effects on academic outcomes (Macaro et al, 2018).…”