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…

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 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…

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…

The influence of individual difference variables on second language (L2) listening comprehension has been an area of research that has been gaining renewed attention in recent years. The current study investigated the effects of two cognitive variables, aptitude and metacognitive awareness, on 107 native-Korean, English as a foreign language…

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…

In this study, we propose a hypothesis that domain-general auditory processing, a perceptual anchor of L1 acquisition, can serve as the foundation of successful post-pubertal L2 learning. This hypothesis was tested with 139 post-pubertal L2 immersion learners by linking individual differences in auditory discrimination across multiple acoustic…

Event-related potentials (ERPs) have become widespread in second language acquisition (SLA) research and a growing body of literature has been produced in recent years. We surveyed 61 SLA papers that use ERPs to study L2 sentence processing in healthy late learners. Our main aim was to provide a critical summary of findings from the decade…

Language learning strategies (LLS) research began in the mid-1970s with the main idea of individual differences in learning a foreign language focusing primarily on the characteristics of a good language learner. In the literature review, the use of LLS has been reported to have a positive influence on proficiency. The goal of this research is to…

Spanish-speaking students constitute the largest subgroup of emergent bilingual (EB) students in the United States. Using longitudinal data on a nationally representative sample of Spanish-English EBs, we explore profiles of English reading trajectories and how early individual differences (i.e., early Spanish reading and English oral proficiency)…

The English language is a catalyst for economic growth, modernization, and globalization. In this milieu, English language competency--defined as the practical ability to use English effectively in diverse contexts, encompassing linguistic, cognitive, and intercultural skills--is recognized as an essential skill (Amor et al., 2023). Research on…

This project examines whether second-language (L2) learners can converge on a native-like pattern at the interface between syntax and discourse under low and high processing pressure, using Spanish clitic-doubled left dislocation (CLLD) as a test case. The original version of the Interface Hypothesis (IH) predicts that L2 competence on…

The past decade has witnessed a plethora of research to study the relationship between reading strategies and reading comprehension, but few studies have examined the brain functionality; more specifically the relationship between hemispheric dominance and reading strategies. Therefore, this study aimed to investigate whether there would be any…

Over the last two decades, there has been an increasing interest in third language (L3) phonology (Cabrelli Amaro, 2012; Cabrelli Amaro & Wrembel, 2016). However, research so far has been primarily directed at specific stages of learning and has independently explored either production (e.g., Llama, Cardoso, & Collins, 2010; Llama &…

The sentence repetition (SR) test is considered as a promising diagnostic tool for detecting language proficiency in monolingual learners, but less is known about its potential to identify dual language learners' (DLLs) linguistic proficiency. Considering that challenges with language learning, such as developmental language disorders (DLDs), is…