Research into second language acquisition (SLA) has shown that individual difference (ID) variables can be strong predictors of language achievement (e.g., Dornyei, 2003; Skehan, 2003). Traditionally, this research conceptualized ID variables as static and monolithic variables (e.g., Dornyei, 2010). More recently scholars have questioned this…

A growing body of evidence demonstrates that individual differences in declarative memory may be an important predictor of second language (L2) abilities. However, the evidence comes from studies using different declarative memory tasks that vary in their reliance on verbal abilities and task demands, which preclude estimating the size of the…

"Variability" and "fractality," two key concepts in Complex Dynamic Systems Theory (CDST)--the former concerning changes and variations, and the latter concerning recursiveness and self-similarities--may seem contradictory at first glance. This forum piece attempts to elucidate how the two seemingly contradictory properties can…

Network analysis is a method used to explore the structural relationships between people or organizations, and more recently between psychological constructs. Network analysis is a novel technique that can be used to model psychological constructs that influence language learning as complex systems, with longitudinal data, or cross-sectional data.…

Positive psychology (PP) is currently employing its modern research toolkit to examine how individual differences of hedonic (i.e. pursuing pleasure, fun, and painlessness) versus eudaimonic (i.e. pursuing meaning, self-worth, and growth) well-being motives play out against emotional and learning challenges or outcomes in life. Similarly oriented,…

The present study aimed to validate a 70-item Korean bilingual version of the Vocabulary Size Test (VST) using Rasch modeling. The goal was to assess the applicability of this Korean version of the VST for Korean learners of English in an English as a foreign language (EFL) context by examining validity evidence based on Messick's framework.…

This review paper explores the role of individual differences in second language vocabulary learning, focusing on three key factors: out-of-class exposure (e.g., viewing TV, playing video games and listening to songs), strategic vocabulary learning, and motivation. Individual differences significantly impact vocabulary learning, making it crucial…

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…

Relatively few studies in the field of second language acquisition have undertaken to investigate the interrelationships of constellations of individual difference variables. This is certainly true of how complexes of ID factors impact motivation to learn an additional language. In order to address this gap, the paper reports a study that examined…

How people conceptualize learning is related to real-world educational consequences across many domains of education. Despite its centrality to the educational system, we know little about how the public reasons about language acquisition, and the potential consequences for their thinking about real-world issues (e.g., policy endorsements). The…

How could individual differences in processing non-speech acoustic signals influence their cue weighting strategies for L2 speech contrasts? The present study investigated this question by testing forty L1 Chinese-L2 English listeners with two tasks: one for testing the listeners' sensitivity to pitch and temporal information of non-speech…

Researchers have agreed that language anxiety is situation-specific; however, whether existing instruments measure stable or transient components of this anxiety remains controversial. Therefore, this study examined language anxiety's trait stability and state variability. The results from synthesizing 21 test-retest correlations based on existing…

In many contexts of multilingualism, language learners can initiate communication in the target language (TL), or a contact language (such as English). Patterns of use emerging from these choices affect TL development. They also vary between individuals. Willingness to communicate (WTC) needs to be investigated in ways that capture these…

This longitudinal study with time-serial data examines for the first time whether different types of intraindividual variation in second language (L2) performance and cognitive functioning are related, and how and when they influence L2 development longitudinally in older adulthood. We analyzed the L2 development of 26 German-speaking adults aged…

This book highlights the roles of several individual difference (ID) variables on the language learning process, exploring them from both the students' and the teachers' perspectives. It presents the results of a large-scale, mixed-methods investigation which was conducted with secondary school pupils and their teachers in Hungary. The…