This study investigated the effect of phonological neighborhood density (PND) on the lexical encoding of perceptually confusable segmental contrasts and the extent to which the precision of encoding is modulated by phonetic categorization and vocabulary size. Korean learners of English and native speakers of American English completed an auditory lexical decision task that contained words and nonwords with /ɛ/, /æ/, /f/, and /p/ (/æ/ and /f/ do not exist in Korean), two phonetic categorization tasks (/ɛ/−/æ/ and /f/−/p/), and a vocabulary test. For the Korean group, participants’ categorization of /f/−/p/ was the only significant predictor of /f/−/p/ nonword rejection. For /ɛ/−/æ/, nonword versions of high PND words were rejected more accurately than low PND. Additionally, vocabulary size and phonetic categorization significantly interacted so that as perception abilities improve, the benefits that come from having a large vocabulary grow as well.

The present study examines whether age of second language acquisition, duration of exposure to that language, and chronological age determine vocabulary knowledge in 214 Russian–Hebrew bilinguals (ages 19–80, immigration ages 1–46, and exposure duration 7–63 years). Participants reported their language background and completed a multiple-choice vocabulary test in Hebrew, alongside other objective tests of Russian and Hebrew proficiency. While vocabulary scores were below age-matched norms for native Hebrew speakers, they were similar to those of younger native speakers matching in exposure duration. Raw vocabulary scores were similar whether participants immigrated up to age 15 or after that age, although results indicated a negative association between age of immigration and vocabulary scores. A positive association emerged between exposure duration and vocabulary scores, and when analyzing all measures together, age of immigration did not predict vocabulary scores, whereas exposure duration was its main determinant. We suggest that bilingualism itself does not cause a vocabulary gap, and that bilinguals’ vocabulary knowledge in their second language improves with exposure, as it does in native speakers throughout adulthood. The study emphasizes that learning a foreign language requires extensive exposure and that vocabulary learning is a lifelong process.

Degrees, unlike entities or events, refer to comparative qualities and are closely tied to gradable adjectives such as “tall.” Degree expressions have been explored in second language (L2) research, covering areas such as learnability, first language (L1) transfer, contrastive analysis, and acquisition difficulty. However, a computational approach to the learning of degree expressions in L2 contexts, particularly for L1 Chinese learners of English, has not been thoroughly investigated. This study aims to fill this gap by utilizing natural language processing (NLP) methods, drawing insights from recent advancements in large language models (LLMs). This study extends Cong (2024)’s general-purpose assessment pipeline to specifically analyze degree expressions, predicting that surprisal metrics will correlate with proficiency levels and distinct developmental stages of L2 learners. Crucially, we address the limitations of surprisal metrics in capturing underuse or avoidance—common in L2 development—by integrating frequency-based analyses. Using an NLP pipeline developed with Stanza, we automatically identified and analyzed degree expressions, constructing linear mixed-effects models to track L2 development trajectories. Our findings reveal that as proficiency increases, learners use complex degree expressions more frequently, supporting theories linking difficulty and learnability. Higher surprisal values are associated with lower proficiency in using degree expressions, and these surprisals are more predictive of degree expressions proficiency than classic NLP measures. These results add further evidence that LLMs and NLP tools provide valuable insights into L2 development, specifically in the domain of degree expressions, expanding upon previous research and offering new approaches for understanding L2 learning processes.

In this study, we approximately replicated Papi and Khajavy’s (2021) investigation into the regulatory focus in second language acquisition, applying their approach to a significantly larger cohort of 855 Chinese second language (L2) learners. In contrast with the original study, our research employed the College English Test Band 4 (CET-4), a standardized English test, to better align with the Chinese educational context. This methodological shift allowed for a nuanced exploration of the regulatory focus’s role in language learning among Chinese students. Our results predominantly reinforce the crucial role of regulatory focus in language learning, echoing Papi and Khajavy’s findings. We discovered notable parallels in how promotion positively influences ideal own and ideal other, and how prevention negatively impacts ought own and ought other. However, a unique finding of our study was the stronger impact of ought selves on L2 anxiety and enjoyment in the Chinese context. This highlights the nuanced influence of socioeducational environments on regulatory focus strategies, suggesting contextual variability in language learning strategies.

The ability to acquire the speech sounds of a second language has consistently been found to be constrained with increasing age of acquisition. Such constraints have been explained either through cross-linguistic influence in bilingual speakers or as the result of maturational declines in neural plasticity with age. Here, we disentangle these two explanations by investigating speech production in adults who were adopted from China to Sweden as toddlers, lost their first language, and became monolingual speakers of the second language. Although we find support for predictions based on models of bilingual language acquisition, these results cannot be explained by the bilingual status of the learners, indicating instead a long-term influence of early specialization for speech that is independent of bilingual language use. These findings are discussed in light of first-language interference and the theory of maturational constraints for language acquisition.

In light of findings from research on informal foreign/second language (L2) learning, with a focus on English as a target language and using the concept of extramural English (EE), this position paper argues that learners’ engagement in EE (through activities such as watching television or films or playing digital games) constitutes an important individual difference (ID) variable that needs to be included in studies that aim to measure L2 English proficiency or development. In addition, it is suggested that if EE as an ID variable is left out in such studies in the future, the rationale for exclusion should be clearly stated. This position paper also discusses research instruments and methods used in this area of research, the benefits and drawbacks of different methods, and identifies research gaps and under-researched learner groups. Further, it is argued that in some contexts, EE has replaced classroom activities as the starting point for and foundation of learning English.

Response times (RTs) have become ubiquitous in second language acquisition (SLA) research, providing empirical evidence for the theorization of the language learning process. Recently, there have been discussions of some fundamental psychometric properties of RT data, including, but not limited to, their reliability and validity. In this light, we take a step back to reflect on the use of RT data to tap into linguistic knowledge in SLA. First, we offer a brief overview of how RT data are most commonly used as vocabulary and grammar measures. We then point out three key limitations of such uses, namely that (a) RT data can lack substantive importance without considerations of accuracy, (b) RT differences may or may not be a satisfactory psychometric individual difference measure, and (c) some tasks designed to elicit RT data may not be sufficiently fine-grained to target specific language processes. Our overarching goal is to enhance the awareness among SLA researchers of these issues when interpreting RT results and stimulate research endeavors that delve into the unique properties of RT data when used in our field.

High-quality replication studies are widely understood to be critical to the growth and credibility of our discipline, as shown in commentaries and discussion since the 1970s, at least. Nevertheless, misunderstandings and limitations in the aims, designs, and reporting of replication research remain, thus reducing the usefulness and impact of replications. To address this issue and improve the rigor, quality, and conduct of replication studies in applied linguistics, a new standard for reporting replication studies that captures several critical features of replication research not discussed in current reporting guidelines is proposed. Importantly, this standard applies basic expectations in replication reporting so that outcomes can be better understood and evaluated. By applying this standard, replication studies will better meet their aims to confirm, consolidate, and advance knowledge and understanding within applied linguistics and second language research. In addition, readers will more easily understand how the replication study was carried out and be able to better evaluate the claims being made.

This paper aims to guide the training of all Latin instructors and learners who want to optimise the process of acquiring the language by applying the results of research carried out in the field of Second Language Acquisition (SLA), specifically here those related to the acquisition of vocabulary. Consequently, some theoretical considerations on the psycholinguistic operations that govern vocabulary learning are first offered, in order to build a better understanding of language acquisition and to make instructors and learners more knowledgeable about the vocabulary learning process, from the noticing of an unknown word and its integration into the subject's competence to the expansion and development of knowledge about the acquired words. The theoretical aspects of vocabulary learning will be illustrated at all times with practical examples taken from methods and books for learning Latin, as well as, in the fourth section, with a wide catalogue of practical advice – must-do items for the class – that can be easily implemented by Latin instructors.