This study addresses the role of domain-general mechanisms in second-language learning and knowledge using an individual differences approach. We examine the predictive validity of implicit-statistical learning aptitude for implicit second-language knowledge. Participants (n = 131) completed a battery of four aptitude measures and nine grammar…

Aptitude-treatment interaction (ATI) research is of both theoretical and practical interest to second language (L2) learning, since it provides insights into the processes linking learner-internal individual difference factors and learner-external contextual variables including instructional approach--variables that jointly determine L2 outcomes.…

Widespread use of the Modern Language Aptitude Test (MLAT) in L2 studies of individual differences implicitly assumes that L2 aptitude is a distinct cognitive facet. There is considerable evidence for prediction from L1 abilities to L2 learning. In this longitudinal study, L1-MLAT-L2 relations were examined in 307 US secondary students based on…

Pragmatic abilities are fundamental to successful language use and learning. Individual differences studies contribute to understanding the psychological processes involved in pragmatic reasoning. Small sample sizes, insufficient measurement tools, and a lack of theoretical precision have hindered progress, however. Three studies addressed these…

This paper examines evidence for relationships among individual differences (IDs) in L1 achievement, L2 aptitude, and L2 achievement. It begins by providing an overview of my academic journey from L1 educator to L2 researcher and explains the development of the Linguistic Coding Differences Hypothesis (LCDH). Next, I review Peter Skehan's…

This book traces and summarizes the author's theoretical insights and empirical findings in the field of foreign language education. The volume explores themes such as individual differences in L1 ability and their connection to L2 aptitude and L2 achievement, L2 anxiety as an affective or cognitive variable, and the relationship between L1 and L2…

Researchers across many fields have called for greater attention to heterogeneity of treatment effects--shifting focus from the average effect to variation in effects between different treatments, studies, or subgroups. True heterogeneity is important, but many reports of heterogeneity have proved to be false, non-replicable, or exaggerated. In…

This study is the first attempt to explore the relationship between rater variables focusing on raters' language aptitude and their judgments of second language (L2) speech. Thirty-four English listeners rated 65 spontaneous native and nonnative speech samples for comprehensibility, accentedness, and fluency. They also completed the LLAMA language…

While evidence has accumulated to support the argument of shared computational mechanisms underlying language comprehension between humans and large language models (LLMs), few studies have examined this argument beyond native-speaker populations. This study examines whether and how alignment between LLMs and human brains captures the homogeneity…

Recent years have witnessed a growing interest in case studies and surveys by researchers of second language acquisition (SLA) and cognitive (neuro-)science to probe into the group of exceptionally talented multilingual learners or polyglots who can understand and speak an impressive number of multiple foreign languages other than their own mother…

The purpose of this study was to find out, whether three methods of presenting input, were effective in relation to language aptitude. Persian-speaking learners of English were provided with 20 grammatical collocations (verb-preposition collocations) embedded in authentic passages, lexically/grammatically elaborated passages, and…

This article revisits the role of cognitive individual differences in creating synergies between second language (L2) writing and second language acquisition research that were proposed by Kormos (2012). It takes stock of the advances in research findings, in the past decade, on the role of working memory and language learning aptitude in L2…

Whereas a growing amount of attention has been directed to the role of perceptual-cognitive aptitude in successful second language (L2) lexicogrammar learning, scholars have begun to investigate the same topic in the context of L2 pronunciation learning. To date, there is ongoing discussion on the mechanism underlying L2 speech learning in…

How does language shape mathematical development? In this article, we consider this question by reviewing findings from cross-sectional and longitudinal research. In this literature, we find that differences in the structures of languages and individual variations in language ability are associated with mathematical performance in both obvious and…

This study examined the simultaneous effects of L2 individual difference (ID) variables (aptitude, motivation, strategy use, language processing experience, and gender) on English as a foreign language (EFL) breadth and depth of L2 vocabulary knowledge of 492 Korean university-level learners. Independent variable measures included the: (1) Korean…