["TESOL Quarterly, EarlyView. ", "\nAbstract\nPsycholinguistics seeks to explain how language is represented, processed, and acquired in the mind. In applied linguistics, this endeavor extends to understanding how diverse bilingual populations—including second language learners, heritage speakers, and individuals experiencing language attrition—acquire and use language across contexts. This article traces the historical and conceptual development of applied psycholinguistics, from early debates on Universal Grammar and the role of consciousness to contemporary accounts centered on implicit learning mechanisms such as statistical learning, prediction, and adaptation. Two exemplary studies illustrate how psycholinguistic constructs—construction reuse, structural priming, and prediction error—can be operationalized to explain fluency development and syntactic learning in instructed settings. Building on these examples, I outline key principles of rigorous research, emphasizing transparent reporting, preregistration, replication, and open sharing as powerful mechanisms for aligning scientific incentives with cumulative knowledge building. Finally, I argue that the future of applied psycholinguistics depends on expanding its empirical base beyond university populations and leveraging online experimentation to enhance both inclusivity and ecological validity. Together, these developments position applied psycholinguistics as a field that not only advances theoretical understanding but also embraces methodological rigor, ethical responsibility, and broader societal relevance.\n"]