In this focused methodological synthesis, the sample construction procedures of 110 second language (L2) instructed vocabulary interventions were assessed in relation to effect size-driven sample-size planning, randomization, and multisite usage. These three areas were investigated because inferential testing makes better generalizations when…

Complex Dynamic Systems Theory (CDST), an instantiation in applied linguistics of complexity epistemology that transcends disciplinary boundaries, has gained much traction and momentum over the last decade, finding expressions in a fast-growing number of empirical second language developmental studies. However, the literature, while rapidly…

The current study set out to examine to what degree age of acquisition (AOA), defined as a learner's first intensive exposure to a second language (L2) environment, mediates the final state of postpubertal, spoken vocabulary attainment. In Study 1, spontaneous speech samples were elicited from experienced Japanese users of English (n = 41) using…

Research on the second language (L2) acquisition of the Spanish copulas has been central to our understanding of key concepts and issues in the field of SLA such as stages of development and variability in L2s. However, this research has focused nearly exclusively on native English-speaking learners. The present study examined native…

In the current study, we examined the role of first-language (L1) influence on the additional-language development of grammatical gender marking in Spanish. The participants were L1 speakers of English or French (N = 215), who were learning Spanish and who were at three instructional levels. The data came from their use of gender marking in…

As survey research in second language acquisition grows in popularity, the adherence to best practices associated with questionnaire quality is critical for a better understanding of factors that influence second language (L2) development. To ensure that a self-report scale targets the construct of interest and does it consistently and accurately,…

Twenty years ago, a state-of-the-art review in "SSLA" marked the coming of age of the study of temporality in second language acquisition. This was followed by three monographs on tense and aspect the next year. This article presents a state-of-the-scholarship review of the last 20 years of research addressing the aspect hypothesis (AH)…

Evidence for the role of procedural memory in second language (L2) acquisition has emerged in our field. However, little is known about the reliability and validity of the procedural memory measures used in this research. The present study (N = 119) examined the reliability and the convergent and discriminant validity of three assessments that…

The study investigates how psychological and social factors relate to productive collocation knowledge in late L2 learners of Swedish (French L1) (N = 59). The individual factors are language aptitude (measured through the LLAMA aptitude test), reported language use, social networks, acculturation, and personality. Multiple linear regression…

This study explored the interaction between learning conditions, linguistic complexity, and first language (L1) syntactic transfer in semiartificial grammar learning by conceptually replicating and extending Tagarelli et al. (2016). We changed the L1 background, elicited production data during debriefing, and added a binary mixed-effects logistic…

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…

This study investigates the acquisition of the constraints regulating subject position in the L2 Spanish spoken by English native speakers and provides a representational account following the premises of the Multiple Grammars (MG) model. The acceptability of preverbal and postverbal subjects is compared considering different discursive contexts…

We investigated age-related decline in adult learning of Dutch as an additional language (Ln) in speaking, writing, listening, and reading proficiency test scores for 56,024 adult immigrants with 50 L1s who came to the Netherlands for study or work. Performance for all four language skills turned out to decline monotonically after an age of…

The present study examined the effects of part and whole learning on the acquisition of second language (L2, English) vocabulary. In whole learning, the materials to be learned are repeated in one large block, whereas, in part learning, the materials are divided into smaller blocks and repeated. Experiment 1 compared the effects of the following…

This study explores the second language (L2) acquisition of a segment that exists in learners' first language (L1) and in their L2 but that differs in its phonetic realization and allophonic patterning in the two languages. Specifically, this research tracks development in one aspect of the production of the alveolar lateral /l/ in the L2 Spanish…