In applied linguistics generally and bilingualism research in particular, psychological variables remain a much under-investigated sub-category of individual differences compared with cognitive ones. To better understand the under-researched psychological effects of bilingualism, this study investigated well-being, a psychological construct, based on a big-data survey. Drawing upon a national survey (N = 12,582), we examined the influence of bilingualism (operationalised as foreign language (FL) proficiency) and 13 sociobiographical variables (e.g., socio-economic status, SES) on well-being. Among these 14 initial independent variables, perceived social fairness, SES, and health emerged as important predictors for well-being, with FL proficiency and national language (NL) proficiency as potentially important predictors; crucially, FL proficiency was more important than NL proficiency. As the first systematic attempt to link bilingualism with well-being, our study advocates (1) a more holistic perspective towards language (including NL and FL(s)) in any bilingual context and (2) fuller use of effect sizes.

The effects of bilingual language experience on cognitive control are still debated. A recent proposal is that being bilingual enhances attentional control. This is based on studies showing smaller effects of the nature of the preceding trial on the current trial in bilinguals (Grundy et al., 2017). However, performance on such tasks can also be accounted for by lower-level processes such as the binding and unbinding of stimulus and response features. The current study used a Partial Repetition Cost paradigm to explicitly test whether language experience can affect such processes. Results showed that bi- and monolinguals did not differ in their responses when the stimulus features were task-relevant. However, the bilinguals showed smaller partial repetition costs when the features were task-irrelevant. These findings suggest that language experience does not affect lower-level processes, and supports the view that bilinguals exhibit enhanced attentional disengagement.

Being bilingual confers certain behavioral effects. Determining their precise origin is of utmost importance given the need to avoid unjust misattribution of labels such as “bilingual (dis)advantage” to people's bilingual experiences. To this end, this systematic PRISMA-based review aims to shed light on the social and sociolinguistic origins of bilingualism-related behavioral effects. Analyzing 368 studies, we find that 73.41% of the 267 studies that report such effects attribute them either to sociolinguistic factors alone or to the interaction of sociolinguistic and cognitive factors. Linking the two fronts, type of effect and origin of effect, we find a previously unreported correlation: Studies that find evidence for bilingual disadvantages are more likely to claim a sociolinguistic origin, while studies that report advantages are more likely to link their findings to a cognitive origin. We discuss these results and present the key components of a sociolinguistic theory of the origin of bilingual effects.

Contraction of want to to wanna is sometimes possible (e.g., Who do you want to/wanna stay with ___ ?), but sometimes impossible (e.g., Who do you want ___ to/*wanna stay?). This contrast is attributable to the grammatical constraint that a wh-trace blocks the contraction of want and to. Most first language (L1) and second language (L2) acquisition studies testing learner knowledge of this constraint have used elicited production tasks and focused on adult participants, with inconsistent results. Using a child-friendly acceptability judgment task, the current study shows that children as young as 3;11 and both child and adult L2 learners have target-like knowledge of the constraint on wanna contraction. This result is in line with the position that L1 acquisition, child L2 acquisition, and adult L2 acquisition are qualitatively similar.

Previous research has shown that bilingual speakers may be more tolerant to ambiguity, they might perceive situations of ambiguity more interesting, challenging and desirable (e.g., Dewaele & Li, 2013). To our knowledge, no data are available addressing the question whether the language in use can have an effect on the personality trait of tolerance of ambiguity (ToA). This study investigated whether and how reading statements in a second language (L2), as opposed to the native language (L1), affects ToA. 387 Italian–English bilingual adults completed a questionnaire measuring levels of ToA either in English or Italian. Results revealed that processing information in L2 promoted higher scores of ToA overall and in sentences that were related to challenging perspectives and change. Age, gender and L2 proficiency were significant predictors of higher ToA scores. This study offers new evidence that processing information in a L2 can affect tolerance of ambiguous situations.

Structural and functional brain adaptations in bilingual speakers are well documented in the neurolinguistic literature. However, far less is known about neural changes evidenced in multilingual speakers. This study investigates brain plasticity in a group of highly proficient multilinguals, fluent in four or more languages, compared to a group of monolinguals. An ROI analysis used to evaluate differences in core linguistic regions and regions associated with language control revealed robust decreases for multilinguals in grey matter thickness of two brain regions within the parietal lobe (i.e., precuneus and angular gyrus), involved in lexico-semantic processing, memory retrieval, and control maintenance. We discuss our findings in the context of emerging models characterizing trajectorial changes in brain structures associated with language experience. We consider how the demands of optimal functioning within multi-linguistic environments may foster cortical changes that manifest as decreased GM thickness in highly proficient multilingual compared to monolinguals.

Code-switching, switching between different languages within the same conversation, is a prominent feature in bilingual communication. This study aimed to elucidate to what extent the linguistic abilities and age of dual-language-learning preschoolers influence the frequency and purposes of code-switching (compensatory, to bridge linguistic gaps; preferential, to express content as fluently as possible; pragmatic, to phrase something appropriately for the situation). Parental code-switching ratings of 101 German/French–Turkish/Italian dual-language learners aged 32–78 months were analyzed. Generalized linear mixed models revealed positive but no negative effects of societal- and heritage-language skills on children's code-switching frequencies independent of switching purposes and with no evidence of age effects. Hence, code-switching across the preschool age mainly reflects high linguistic competences. Models with linguistically and psychometrically parallelized language scores indicated a strong switching tendency toward the societal language when proficiency in both languages is high, and away from the societal language when language proficiencies are low.

Learning a new language is an important goal that many individuals find difficult to achieve, particularly during adulthood. Several factors have related this variability to different extrinsic (learning condition, difficulty of the materials) and intrinsic (cognitive abilities) factors, but the interaction between them is barely known. In two experiments, participants learned English grammar rules in intentional (Experiment 1) or explicit (Experiment 2), and incidental learning-contexts. Overall, results of this study indicated that intentional-explicit conditions benefitted rule-learning, as compared to incidental conditions. This benefit was mainly present when participants were learning an easy-rule; explicit and incidental learning did not differ in the case of participants learning a difficult rule (Experiment 2). Moreover, individual differences in executive functioning predicted successful learning in interaction with difficulty. When learning an easy-rule, proactive control facilitated intentional learning. In contrast, when participants were learning a complex-rule, incidental learning was enhanced by lower involvement of proactive control.

The aim of our study was to examine the longitudinal associations between two forms of second language (L2) knowledge (i.e., explicit and implicit knowledge) and the activity types that facilitate different processing mechanisms (i.e., form- and meaning-focused processing). L2 English speakers completed two tests of explicit knowledge (untimed written grammaticality judgment test and metalinguistic knowledge test) and three tests of implicit knowledge (timed written grammaticality judgment test, oral production, and elicited imitation) at the beginning and the end of a semester of university-level study. To track engagement in the activity types, participants completed self-reported language exposure logs across five days throughout the semester. The results from an autoregressive cross-lag analysis suggest L2 explicit and implicit knowledge influenced each other reciprocally over time. Neither activity type predicted knowledge development. We conclude that language acquisition is a developmental process typified by a dynamic, synergistic interface between explicit and implicit knowledge.

To date, the evidence regarding the effect of bilingualism/multilingualism on short-term memory (STM) and working memory (WM) capacity is inconclusive. This study investigates whether multilingualism has a positive effect on the verbal STM and WM capacity of neurotypical middle-aged and older individuals. Eighty-two L1-Norwegian sequential bilingual/multilingual academics were tested with tasks measuring verbal STM/WM capacity. Degree of bilingualism/multilingualism for each participant was estimated based on a comprehensive questionnaire. Different measures of bilingualism/multilingualism were used. Data on potentially influencing non-linguistic factors were also collected. Correlation and regression analyses showed that multilingualism impacts both verbal STM and verbal WM. In particular, all analyses showed that number of known foreign languages was the strongest predictor of verbal STM and WM capacity. The results are discussed in light of recent studies on the impact of bilingualism on STM/WM and on recent proposals regarding the mechanism underlying so-called bilingual advantage.

This study explored how bilingual code-switching habits affect cognitive shifting and inhibition. Habitual code-switching from 31 Mandarin–English bilingual adults were collected through the Language and Social Background Questionnaire (Anderson, Mak, Keyvani Chahi & Bialystok, 2018) and the Bilingual Switching Questionnaire (Rodriguez-Fornells, Krämer, Lorenzo-Seva, Festman & Münte, 2012). All participants performed verbal and nonverbal switching tasks, including the verbal fluency task, a bilingual picture-naming and colour-shape switching task. A Go/No-go task was administered to measure the inhibitory control of participants.

Frequent bilingual switchers showed higher efficiency in both English to Chinese verbal switching and nonverbal cognitive shifting. Additionally, bilinguals with intensive dense code-switching experience outperformed in the Go/No-go task. In general, the study revealed the connections between bilinguals’ intensity of single-language context experience and goal maintenance efficiency, which partially supported the Adaptive Control Hypothesis’ prediction (Green & Abutalebi, 2013). Besides, it also indicated the facilitations of bilinguals’ dense code-switching experience on their conflicts monitoring and response inhibition.

In “The Devil's Dictionary”, Bierce (1911) defined language as “The music with which we charm the serpents guarding another's treasure.” This satirical definition reflects a core truth – humans communicate using language to accomplish social goals. In this Keynote, we urge cognitive scientists and neuroscientists to more fully embrace sociolinguistic and sociocultural experiences as part of their theoretical and empirical purview. To this end, we review theoretical antecedents of such approaches, and offer a new framework – the Systems Framework of Bilingualism – that we hope will be useful in this regard. We conclude with new questions to nudge our discipline towards a more nuanced, inclusive, and socially-informed scientific understanding of multilingual experience. We hope to engage a wide array of researchers united under the broad umbrella of multilingualism (e.g., researchers in neurocognition, sociolinguistics, and applied scientists).

In the present meta-analysis, we investigated the robustness and the magnitude of the Foreign Language Effect (FLE) – that is, the putative effect of language context (native versus foreign language) on decision-making. We also investigated whether the FLE is moderated by language experience – measured by second language age of acquisition and proficiency – or by methodological choices – the types of decision problems adopted, the presentation modality of the tasks administered, and the perspective in which problems are framed. Our results showed a reliable FLE, which was not moderated by language experience or methodological choices. We discuss our findings in relation to available theories of FLE, and indicate possible future directions to improve our understanding of the interplay between bilingualism and decision-making.

Questionnaires documenting children's bilingual experience have been used frequently in research on language and cognitive development. However, there has been little investigation of the comparability between these tools. In this review, we (i) provide a list of available questionnaires used to quantify bilingual experience in children; (ii) identify the components of bilingual experience documented across questionnaires; and (iii) discuss the comparability of the measures used to operationalise these components. In doing so, we review 48 questionnaires and identify 32 overarching constructs, manifested as 194 components, and we calculate the frequency with which they are documented. Finally, by focusing on a subset of overarching constructs (language exposure and use, activities, and current language skills), we observe high variability in how they are operationalised across tools. These findings highlight the need for greater transparency in how we document bilingualism and for more comparable measures.

How can we leverage digital technologies to enhance language learning and bilingual representation? In this digital era, our theories and practices for the learning and teaching of second languages (L2) have lagged behind the pace of scientific advances and technological innovations. Here we outline the approach of digital language learning (DLL) for L2 acquisition and representation, and provide a theoretical synthesis and analytical framework regarding DLL's current and future promises. Theoretically, DLL provides a forum for understanding differences between child language and adult L2 learning, and the effects of learning context and learner characteristics. Practically, findings from learner behaviors, cognitive and affective processing, and brain correlates can inform DLL-based language pedagogies. Because of its highly interdisciplinary nature, DLL can serve as an approach to integrate cognitive, social, affective, and neural dimensions of L2 learning with new and emerging technologies including VR, AI, and big data analytics.

Research on the effects of bi- and multi-lingualism on brain structure has so far yielded variable patterns. Although it cannot be disputed that learning and using additional languages restructures grey (cortical, subcortical and cerebellar) and white matter in the brain, both increases and reductions in regional volume and diffusivity have been reported. This paper revisits the available evidence from simultaneous and sequential bilinguals, multilinguals, interpreters, bimodal bilinguals, children, patients and healthy older adults from the perspective of experience-based neuroplasticity. The Dynamic Restructuring Model (DRM) is then presented: a three-stage model accounting for, and reinterpreting, all the available evidence by proposing a time-course for the reported structural adaptations, and by suggesting that these adaptations are dynamic and depend on the quantity and quality of the language learning and switching experience. This is followed by suggestions for future directions for the emerging field of bilingualism-induced neuroplasticity.