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…

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…

This book traces and summarizes theoretical insights and empirical findings on the topic of whether or not anxiety for language learning could be a causal variable for individual differences in language learning. The author brings together three decades of research to show that first language (L1) skills and second language (L2) aptitude are…

"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.…

The book explores the relationships between the personality traits of Polish university students learning English as a foreign language and their use of language learning strategies (LLS). It provides a solid theoretical background for the investigation of the interface between the two constructs, describes the applied analytical procedures in…

This study examines Korean L2 learners' production of English phonological contrasts (e.g., consonant-final versus vowel-final forms) that are absent in their L1. Twenty university students divided into high- and low-proficiency groups participated in the study. Their productions were analyzed for segmental accuracy and error patterns. Results…

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…

Although most children learn to communicate in their first language (L1), there is normal and expected variation in their rate of acquisition across all components of the language system. Until recently, most second language acquisition and second language (L2) researchers have assumed that individual differences (IDs) in L1 acquisition are small…

This study investigated L2 Korean speakers' self-assessment of speech comprehensibility and accentedness, including a conceptual replication of Trofimovich, Isaacs, Kennedy, Saito, and Crowther (2016, Experiment 1) and exploratory analyses of individual differences in self-assessment. L2 Korean speakers (N = 198) self-assessed their…

Grit is among the individual difference (ID) variables that have recently come to the attention of researchers investigating second language acquisition. While some empirical evidence has been accumulated, it is clearly scant and limited, also because of the fact that many studies have looked into domain-general grit rather than this attribute as…

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…