Previous research suggests that bilingual language control requires domain-general cognitive control. Recent research suggests that exploration of individual differences is key for understanding the relationship between bilingual language control and cognitive control. The current study used multi-voxel pattern analysis (MVPA) to examine within-subject patterns of fMRI activity in the dorsolateral prefrontal cortex (DLPFC) during bilingual language switching and non-linguistic task-switching. We hypothesized that bilinguals would have identifiable, within-subject patterns of DLPFC activity for both types of switching and that bilinguals and monolinguals would differ in patterns of DLPFC activity for task-switching. We were unable to identify patterns of DLPFC activity associated with bilingual language switching. Task-switching was related to patterns of left DLPFC activity for both bilinguals and monolinguals, and there were identifiable patterns of right DLPFC activity for the bilinguals only. These findings suggest that the DLPFC is not the key brain structure connecting bilingual language and task-switching.

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.

We investigated the neurophysiological mechanisms underlying bi-alphabetic reading using event-related potentials (ERPs). Brain activity was recorded using EEG in a group of Russian–English biliterates during a reading-aloud task with familiar and novel words. Capitalizing on a partial overlap between the Roman and Cyrillic alphabets, the stimuli were presented in L1 Cyrillic, L2 Roman, or in an ambiguous script, in a counterbalanced fashion. The results revealed functional dissociation between the stimuli in terms of processing their graphemic ambiguity. The interference caused by L1-L2 script inconsistencies in novel wordforms was detected at a late processing stage, reflected in N400 response enhancement for unfamiliar script-ambiguous items. Conversely, familiar ambiguous and L2 words showed no N400 increase but demonstrated an early enhancement of the P200 component in comparison to those presented in L1. These results indicate the use of a whole-word reading strategy for familiar words even in ambiguous script, likely triggered by an automatic activation of well-established lexico-semantic representations. The absence of similar top-down mechanisms for novel ambiguous-script words likely results in increased grapheme-to-phoneme decoding effort, with important implications for L2 reading and vocabulary acquisition.

This study investigates whether the cognitive reappraisal strategy is influenced by the participant's language (native/foreign) when confronting a fearful stimulus. Sixty participants with subclinical phobia of cockroaches were exposed to several phobic and neutral pictures while they used cognitive reappraisal in their native language or a foreign one. Electrodermal activity, pupil dilation, and self-reports of affective valence and arousal were collected. Results showed that participants in the foreign context were more effective at using reappraisal to reduce valence self-ratings compared to using no regulation. Also, participants in the foreign context showed greater pupil size when reappraising their emotions, compared to the non-regulation condition. Depending on the language, no differences were found for arousal self-reports or electrodermal activity when using reappraisal. These results suggest that using a foreign language could be advantageous in reducing the negative valence through reappraisal. Psychophysiological results are discussed in light of cognitive effort studies.

To better explain various neurocognitive consequences of bilingualism, recent investigations have adopted continuous measures of bilingual experience, as opposed to binary bi/monolingual distinctions. However, few studies have considered whether bilingualism's effects on cognition are modulated by the linguistic distance (LD) between L1 and L2, and none of the existing studies has examined cognitive consequences of LD in aging populations. Here, we investigated the modulatory role of LD on the relationship between bilingualism, executive performance, and cognitive reserve (CR) in a sample of senior bilinguals. Our results show a dynamic trajectory of LD effects, with more distant language pairs exerting maximum effects at initial stages of bilingual experience – and closer language pairs at advanced stages. Bilingualism-related CR effects emerged only in the individuals with closer language pairs, suggesting that the language control stage of bilingual experience may play a key role in CR accrual, as compared to the L2 learning stage.

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.

In two online survey studies (N = 688 and N = 247, respectively) we developed and validated a new psychometric scale for measuring emotional resonance reduction in bilinguals’ LX (“later learnt language”) relative to their L1 (“first language”). The final scale, dubbed RER-LX (for Reduced Emotional Resonance in LX), comprises 15 items and possesses a number of desirable psychometric properties. It yields good test reliability (expected alpha between 0.8 and 0.9), produces near-normally distributed test scores, and exhibits content validity in terms of its underlying factor structure. Moreover, it correlates well with the only other instrument previously used for the same purpose (BEQ subscale comprising BEQ-swearing, BEQ-feelings and BEQ-anger). However, compared to the BEQ items, RER-LX has significantly better discriminant validity in relation to LexTALE, a widely used measure of proficiency in English as a second language. Our new scale will be useful to researchers studying bilingualism and emotion.

This study explores the relationship between executive functioning (EF) and degree of bilingualism in a sample (N = 79) of 5- to 7-year-old monolingual and bilingual children. The bilingual group included children who are fully fluent in two languages (balanced bilinguals) and children who are still learning their second language (dual-language learners (DLLs). In general, findings revealed mixed associations between bilingualism and EF. There were no language group differences for one type of simple inhibitory control (i.e., go or no-go task). However, a bilingual advantage was demonstrated for another type of simple inhibitory control (the Head–Toes–Knees–Shoulders task), for complex inhibitory control (i.e., the Simon effect), and for cognitive flexibility (Dimensional Change Card Sort). Effects were found when DLLs and balanced bilinguals were analyzed separately, and the latter two effects were found when both types of bilinguals were compared to monolinguals. The findings contribute to the growing literature examining a possible bilingual effect in early childhood.

Listeners can use the way people speak (prosody) or what people say (semantics) to infer vocal emotions. It can be speculated that bilinguals and musicians can better use the former rather than the latter compared to monolinguals and non-musicians. However, the literature to date has offered mixed evidence for this prosodic bias. Bilinguals and musicians are also arguably known for their ability to ignore distractors and can outperform monolinguals and non-musicians when prosodic and semantic cues conflict. In two online experiments, 1041 young adults listened to sentences with either matching or mismatching semantic and prosodic cues to emotions. 526 participants were asked to identify the emotion using the prosody and 515 using the semantics. In both experiments, performance suffered when cues conflicted, and in such conflicts, musicians outperformed non-musicians among bilinguals, but not among monolinguals. This finding supports an increased ability of bilingual musicians to inhibit irrelevant information in speech.

Previous studies that contrasting bilinguals with monolinguals on Theory of Mind (ToM) have shown mixed results. We present a relatively large (N = 102) study comparing Polish–English sequential bilinguals living in the UK with Polish monolinguals living in Poland. Going beyond a simple group comparison, we explored the role of language proficiency and input in ToM abilities. A battery of eight tasks was used to measure ToM, and the groups were matched on age, gender, SES, IQ and L1 word comprehension. Although bilinguals did not differ from monolinguals in accuracy in ToM tasks, they demonstrated better reasoning abilities when providing justification for ToM responses. ToM accuracy scores were best predicted by L1 proficiency, but the justification scores were best predicted by both L1 and L2 proficiency. The findings suggest that the nuances of bilingual experience provide an important scaffolding context for ToM development.

The present study asked whether oral vocabulary training can facilitate reading in a second language (L2). Fifty L2 speakers of English received oral training over three days on complex novel words, with predictable and unpredictable spellings, composed of novel stems and existing suffixes (i.e., vishing, vishes, vished). After training, participants read the novel word stems for the first time (i.e., trained and untrained), embedded in sentences, and their eye movements were monitored. The eye-tracking data revealed shorter looking times for trained than untrained stems, and for stems with predictable than unpredictable spellings. In contrast to monolingual speakers of English, the interaction between training and spelling predictability was not significant, suggesting that L2 speakers did not generate orthographic skeletons that were robust enough to affect their eye-movement behaviour when seeing the trained novel words for the first time in print.

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.

For bilinguals, lexical access in one language may affect, or be affected by, activation of words in another language. Research to date suggests seemingly contradictory effects of such cross-linguistic influence (CLI): in some cases CLI facilitates lexical access while in others it is a hindrance. Here we provide a comprehensive review of CLI effects drawn from multiple disciplines and paradigms. We describe the contexts within which CLI gives rise to facilitation and interference and suggest that these two general effects arise from separate mechanisms that are not mutually exclusive. Moreover, we argue that facilitation is ubiquitous, occurring in virtually all instances of CLI, while interference is not always present and depends on levels of cross-language lexical competition. We discuss three critical factors – language context, direction, and modality of CLI – which appear to modulate facilitation and interference. Overall, we hope to provide a general framework for investigating CLI in future research.

BAbSANT (Bilingual Abstract Semantic Associative Network Training) is a novel, theoretically motivated approach to anomia therapy for bilingual persons with aphasia (BPWA). We report on a Russian-dominant, Russian–English BPWA, who was trained on abstract English and Russian words. We hypothesized both within- and cross-language generalization when the non-dominant language was trained, and only within-language generalization when the dominant language was trained. We also hypothesized that cross-language generalization is modulated by nonverbal cognitive control. Results revealed that when English abstract words were trained, within-language generalization to concrete words and cross-language generalization to Russian abstract words was observed, confirming our first hypothesis. However, our second hypothesis was not confirmed. When Russian was trained, direct effects of treatment and within- or cross-language generalization effects were not observed. Our third hypothesis was confirmed. Results from cognitive control tasks from this individual suggest a role of nonverbal cognitive control on cross-language treatment outcomes.

In a between-language lexical priming study, we examined to what extent the two languages in a simultaneous bilingual child's lexicon interact, while taking individual differences in language exposure into account. Primary-school-aged Dutch–Greek bilinguals performed a primed picture selection task combined with eye-tracking. They matched pictures to auditorily presented Dutch target words preceded by Greek prime words. Their reaction times and eye movements were recorded. We tested for effects of between-language phonological priming, translation priming, and phonological priming through translation. Priming effects emerged in reaction times and eye movements in all three conditions, at different stages of processing, and unaffected by language exposure. These results extend previous findings for bilingual toddlers and bilingual adults. Processing similarities between these populations indicate that, across different stages of development, bilinguals have an integrated lexicon that is accessed in a language-nonselective way and is susceptible to interactions within and between different types of lexical representation.

To test effects of German on anticipation in Vietnamese, we recorded eye-movements during comprehension and manipulated i) verb constraints (different vs. similar in German and Vietnamese) and ii) classifier constraints (absent in German). In each of two experiments, participants listened to Vietnamese sentences like “Mai mặc một chiếc áo.” (‘Mai wears a [classifier] shirt.’), while viewing four objects. Between experiments, we contrasted bilingual background: L1 Vietnamese–L2 German late bilinguals (Experiment 1) and heritage speakers of Vietnamese in Germany (Experiment 2). Both groups anticipated verb-compatible and classifier-compatible objects upon hearing the verb/classifier. However, when the (verb) constraints differed (e.g., Vietnamese: mặc ‘wear (a shirt/#earrings)’ – German: tragen ‘wear (a shirt/earrings)’), the heritage speakers were distracted by the object (earrings) compatible with the German (but not the Vietnamese) verb constraints. These results demonstrate that competing information in the two languages can interfere with anticipation in heritage speakers.

Previous developmental studies reported bilinguals’ Theory of Mind (ToM; the ability to take on another's perspective) develops differently than monolinguals. We conducted a scoping review to evaluate how researchers assess bilinguals’ ToM and whether they characterize bilinguals’ lived experiences. We analyzed 53 publications examining ToM in bilinguals, with most papers studying children (n = 42; 79%). We identified 96 different tasks used across these 53 papers. The most common are 46 (48%) cases of the false-belief task, a cognitive-focused task using story vignettes. Few tasks target other types of ToM, such as ToM in social settings or taking others’ emotional perspectives. Furthermore, only half of the papers reported language history (n = 28, 53%) and exposure (n = 25, 47%), limiting the inferrability of ToM and language experiences. Expanding how we study ToM in bilinguals will improve our understanding of the intersection of bilingualism and ToM.

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.