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…

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…

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…

In the process of language learning, individuals must acquire different types of linguistic knowledge, such as the sounds of the language (phonemes), how these may be combined to form words (phonotactics), and morphological rules. Early and late bilinguals tend to perform like natives on second language phonological tasks that involve pre-lexical…

In this article, I describe studies conducted over 25 years with secondary and post-secondary L2 learners in the United States. The evidence from these studies shows that there are important connections between students' early L1 skills and their L2 aptitude and L2 proficiency and that individual differences in students' L1 skills in elementary…