“…Perhaps due to the various approaches to defining L2 proficiency, there seems to be little agreement on how to measure it, especially for the purposes of SLA research. While some of the existing approaches to L2 proficiency assessment have included speed of lexical access (Bairstow et al, 2014), self-assessment (Li & Zhang, 2021;Tigchelaar et al, 2017), course grades (see Brown et al, 2018), C-tests (e.g., Norris, 2018), and corpus-based analysis of learner written and oral production (e.g., Gablasova et al, 2017), researchers are calling for more rigorous and targeted methods of assessing learner proficiency (Derrick, 2016;Norris & Ortega, 2012). Moreover, due to the multifaceted, "fuzzy" nature of proficiency (Carlsen, 2012), problems associated with reliability and validity of nonstandardized L2 proficiency measures have been noted (Alderson, 2007;Hulstijn, 2007;Pienemann et al, 1988).…”