Scott Jarvis is the Stoller-Grabe Endowed Distinguished Chair in Applied Linguistics at Northern Arizona University, and he currently serves as Editor-in-Chief of Language Learning. His main areas of research are crosslinguistic influence, lexical diversity, and forensic linguistics, and across these areas he has played a leading role in shaping several new strands of inquiry. He is one of the principal architects of the study of conceptual transfer—crosslinguistic influence arising from language-specific concepts and patterns of conceptualization—which he developed across a body of work beginning with his 1998 book Conceptual Transfer in the Interlingual Lexicon and his 2008 volume Crosslinguistic Influence in Language and Cognition (with Aneta Pavlenko), and continuing through subsequent work clarifying the construct’s scope and theoretical foundations. He has likewise been instrumental in establishing text-analytic and detection-based approaches to the study of language transfer—including native language identification and text classification, as presented in his 2012 edited volume Approaching Language Transfer through Text Classification—and in advancing the modeling and measurement of lexical diversity as a multidimensional construct grounded in human judgments. His recent research has, inter alia, investigated conceptual transfer and the comprehension and comprehensibility of legal language, particularly non-native speakers’ understanding of their Miranda rights. Professor Jarvis has authored or edited six books and edited volumes and published more than seventy journal articles, book chapters, and reviews. Alongside his current editorship of Language Learning, he has served the journal as Executive Director, and has held leadership roles in the field, including Treasurer of the American Association for Applied Linguistics (AAAL) and co-convener of the AILA Research Network on Crosslinguistic Influence. Additionally, he has served on numerous editorial boards. His contributions have earned recognition including the 2021 AAAL Research Article Award—for his co-authored study of native and non-native speakers’ understanding of their Miranda rights—and an honorary doctorate from the University of Jyväskylä, Finland.

The book is renowned for its novel approach combining psychology, applied linguistics, and cognitive science as well as for its extensive examination of the state of individual differences research. Beyond a basic field review, every chapter explores the theoretical and empirical limits of modern methods. This volume confirms the significance of personal variance in L2 learning. The four main sections of the book, each of which concentrates on a different set of cognitive variables, are age, intelligence, aptitude, and affect (Part I); memory, attention, and noticing (Part II); learning strategies, metacognition, and self-regulation (Part III); L2 skills, learning challenges, and anxiety (Part IV).