Negative Entrenchment and Statistical Preemption in L2 Acquisition: A Scoping Review with Methodological Directions

Recent years have seen a growing number of empirical studies that examine negative entrenchment and statistical preemption as mechanisms of frequency-based learning in second language (L2) acquisition. As the body of research expands, there is a need to take stock of how these mechanisms have been studied and what kinds of evidence have accumulated. This scoping review analyses 24 empirical studies published between 1993 and 2024, focusing on the range of target structures, language backgrounds, task types, and reported outcomes. While both negative entrenchment and statistical preemption have received empirical support, null results were also frequently reported. Crucially, these null results are not confined to specific methodological choices or task types. This review, therefore, examines the conditions under which such mixed findings emerge and shows that they arise at the intersection of L1 influence and broader universal constraints. Building on this analysis, the paper proposes several methodological directions, including simulation-informed Bayesian modelling as an integrative approach and experimental paradigms carefully designed to isolate mechanisms as a disentangling approach. It also highlights the need for greater transparency in sample-size determination, preregistration practices, and other measures that enhance the reliability of future research.