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…

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)…

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 study examines the extent to which extra-linguistic factors such as language dominance, order of acquisition and language of instruction are deterministic for multilingual transfer selection and subsequent development. We test two groups of Catalan-Spanish bilinguals acquiring English as an L3 in a controlled setting. We first examine…

In bilinguals and second language learners, the native (L1) and nonnative (L2) languages coexist and interact. The L1 influences L2 production via forward transfer, as is seen with foreign accents. However, language transfer is bidirectional: even brief experience with an L2 can affect L1 production, via backward transfer. Here, we review the…

Executive function (EF) skills are the attention-regulation skills that make it possible to sustain attention, keep goals and information in mind, refrain from responding immediately, resist distraction, tolerate frustration, consider the consequences of different behaviors, reflect on past experiences, and plan for the future. As EF research…

The Foreign Language Classroom Anxiety Scale (FLCAS) has been challenged on the grounds that it may also assess language learning skills. In this study, 128 students who had been administered measures of first language (L1) skills in elementary school were followed from 1st to 10th grade. Fifty-three students had completed second language (L2)…

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…

Examined, over a 10-year span, continuity in individual differences in cross-modal transfer to visually recognized shapes that had previously been felt but not seen. Found that cross-modal performance showed a left-hand advantage at 11 years. Cross-age correlations were significant when tactual exploration at 11 years was done with the left hand.…