“…There have been several discussions of theories of L2 vocabulary learning (e.g., Barcroft, 2015; Dóczi & Kormos, 2016; Hulstijn, 2001; Kormos, 2020; Laufer, 2020; Moonen, De Graaff, & Westhoff, 2006; Nation, 2013; Nation & Webb, 2011; see also Suzuki, Nakata, & DeKeyser, 2019, for a recent discussion of desirable difficulty; and Lightbown, 2008, on transfer appropriate processing). However, (quasi‐)empirical studies aiming to directly contribute to theory building are relatively scarce, with the majority of these studies focusing on the ILH (but see also Barcroft, 2002, 2003, 2004, 2009, 2019; Kida & Barcroft, 2018, testing the type of processing–resource allocation, or TOPRA, model). The large number of studies investigating the ILH may be due to its strengths of (a) proposing a clear, falsifiable hypothesis; (b) demonstrating how the hypothesis can be tested (Hulstijn & Laufer, 2001); and (c) aiming to provide transparent pedagogical suggestions—the findings of the ILH studies provide pedagogical implications that can easily be applied to vocabulary teaching.…”