Bilingual experience may enhance attentional control, but little work has addressed whether monolinguals and bilinguals differ in allocating attentional resources. Focusing on speech processing, we examined listening effort via pupillometry in English monolinguals and simultaneous bilinguals, while they listened to passages in a familiar or unfamiliar language. Results demonstrated similar pupil responses across conditions in bilinguals, yet monolinguals showed significantly larger pupil size when listening to the unfamiliar language than the familiar one. Further, more English exposure (especially a longer stay in an English-speaking family) correlated with smaller pupil size in the familiar language condition. Overall, our findings suggest that bilinguals tend to exhibit greater listening effort than monolinguals, and a more cognitively demanding situation (i.e., listening to an unknown language) requires more effort in monolinguals. With this, we broadened the scope of research on bilingual cognition and demonstrated that bilingualism affects attentional resource allocation in spoken language processing.

This study investigated whether differences in executive control exist between bilinguals and monolinguals who share a dual-language context. We compared functional monolingual and bilingual groups’ cognitive performance and the correlation between self-reported and objective linguistic variables and cognitive outcomes. Group comparisons revealed no significant differences between functional monolinguals and bilinguals on inhibition, task switching and updating of information. However, distinct correlational patterns were observed within groups. In functional monolinguals, participants with lower bilingualism scores showed better task-specific inhibition (Color–Word part of the Stroop task) and a better ability to monitor for conflicts (Digits Forward task). In contrast, bilinguals with higher degrees of bilingualism showed better overall inhibition outcomes (Stroop effect). Findings are discussed in terms of the importance of adopting more comprehensive methodological approaches to study bilingualism as a heterogeneous phenomenon, considering the diversity within each group and the cultural and linguistic context in which the bilingual experience takes place.

Bilingual speakers have been found to outperform monolingual speakers in tasks which involve taking others’ perspectives. This research examined whether bilingualism improves young adults’ performance on visuospatial perspective-taking (VPT) tasks, independently of culture and executive function (EF). Sixty-three East Asian and 61 European bilingual adults, as well as 60 English monolingual adults took part in level-1 VPT tasks (judging what others can see), level-2 VPT tasks (judging how others can see something) and EF tasks. They also filled in questionnaires about their social and language background, cultural orientation and acculturation. Groups did not differ in terms of VPT, suggesting that adult VPT is not affected by bilingualism or cultural orientation. Hierarchical regression revealed that VPT performance was predicted by EF skills, but not by individual differences in bilingualism or culture.

Previous research has mainly explored the relationship between bilingual language control and domain-general cognitive control through behavioral correlations, often revealing epiphenomenal links rather than causality. This study utilizes transcranial magnetic stimulation (TMS) to investigate the causal roles of the left inferior frontal gyrus (LIFG) and left middle temporal gyrus (LMTG) in 33 unbalanced Chinese-English bilinguals. Continuous theta burst stimulation was applied in separate sessions to decrease cortical excitability, with vertex stimulation as a control. LIFG stimulation significantly increased switching costs in nonverbal switching tasks, highlighting its role in domain-general cognitive control. LMTG stimulation did not affect switching or mixing costs in language or nonverbal switching tasks, suggesting no causal involvement, but it reduced reaction times (RTs) during language switching tasks, underscoring its specialization in language processing. These findings highlight distinctions between the neural mechanisms of bilingual language control and domain-general cognitive control, particularly in the LIFG.

Recent research suggests that bilinguals flexibly adjust distinct types of cognitive control mechanisms to meet the linguistic demands of their language use and exposure contexts. The present study compared two groups of young, Mexican-born, sequential Spanish L1–English L2 bilinguals who reported either separate or integrated use of both languages. Results showed that greater linguistic diversity across social spheres predicted different patterns of engagement in proactive and reactive control for each group. Among separate-context bilinguals, higher linguistic diversity was associated with faster reaction times in both proactive and reactive control, as well as in overall processing speed. Notably, for integrated-context bilinguals, higher linguistic diversity predicted slower responses in proactive control and processing speed. Additionally, a significant relationship emerged between L2 proficiency and accuracy on proactive control trials for separate-context bilinguals. These findings support perspectives emphasizing the interplay between proactive and reactive control as an outcome of bilinguals’ adaptation to contextual linguistic demands. An important implication is that bilingual groups who share the same language pair and are immersed in their L1 environment may nonetheless differ in cognitive performance, with such differences becoming evident when assessed through fine-grained, nonlinguistic cognitive measures.

This study investigates second language (L2) phonetic categorization and phonological encoding of L2 words (hereafter, phonolexical encoding1) with phonemic and allophonic cross-linguistic mismatches. We focus on the acquisition of Spanish /ɾ/-/l/ and /ɾ/-/t/ contrasts among Spanish learners with American English (AE) and Mandarin Chinese (hereafter, Chinese) as first languages (L1s). [ɾ] and [t] are positional allophones in AE but separate phonemes in Spanish. The phoneme /ɾ/ is absent in Chinese. AE learners showed nativelike phonetic categorization and little between-contrast difference in phonolexical encoding, suggesting that L1 positional allophony does not necessarily impede L2 contrast acquisition. Chinese learners showed persistent perceptual difficulties with both contrasts due to perceptual similarity. Phonetic categorization significantly predicted phonolexical encoding for /ɾ/-/t/ contrasts for Chinese learners bidirectionally, while AE learners showed this relationship only when /t/ was incorrectly replaced by /ɾ/ in Spanish words. This asymmetry can be driven by the fact that [t] is the dominant allophone of /t/ in AE, while [ɾ] is a positional allophone. It suggests L1 allophonic knowledge heightens perceptual monitoring when evaluating substitutions that conflict with L1 phonological expectations. This study calls for more nuanced treatment of L1 influence in L2 phonological acquisition models, especially at the allophonic level.

Approximately half of the world’s population is multilingual, and many read in a second language. Thus, an open question is whether and how people’s multilingual knowledge impacts their second language reading processes. To this end, we investigated whether competing influences from people’s first language (L1) writing system (i.e., alphabetic, logographic, or alphasyllabic) impact second language (L2) reading of English (alphabetic). Based on models of L1 and L2 reading, we hypothesized that matches/mismatches in people’s L1 and L2 writing scripts would modulate the expected relationship between L2-English reading proficiency and how often people use their L2 in daily life. Using a subsample of 1073 adults from Siegelman et al. (2023), we found that readers with mismatching L1 writing scripts varied on both English Single Word Accuracy and Speed Measures, and English Extended Word Measures, over and above the expected effects of L2 reading usage. L1-alphabetic and alphasyllabic readers were faster and more accurate than L1-logographic speakers on Single Word Speed and Accuracy Measures. L1-logographic readers were also faster but lower in accuracy on Extended Word Measures vs. L1-alphabetic and alphasyllabic readers. These findings indicate that multilingual knowledge and experience mutually constrain L2 reading and suggest future avenues of theoretical and empirical inquiry.

Sound symbolism refers to a non-arbitrary relationship between speech and non-speech sounds and their meaning. We investigated whether bilingual individuals, due to their exposure to diverse linguistic systems, exhibit an advantage in this domain compared to monolinguals, or whether this ability relies on universal mechanisms independent of linguistic background. Ninety-four bilingual (spoken languages: Italian and at least another language; age ranging from 22 to 66 years, M = 35.31, SE = 1.26) and 101 monolingual participants (all Italian speakers; age ranging from 22 to 64 years, M = 36.05, SE = 1.16) were presented with 120 words from four unknown languages and asked to infer their meaning from three alternatives. Results confirmed the presence of sound symbolism, as overall performance was significantly higher than chance, but no significant differences emerged between monolinguals and bilinguals, suggesting that sound symbolism is an automatic cognitive mechanism, independent of prior linguistic experience.

The richness of bilingual children’s language experience is typically expressed as a composite score using parental questionnaire data. This study unpacks the concept of input richness by examining one such composite score (Q-BEx) to determine whether it reliably predicts children’s language abilities, is no more complex than required, and as user-friendly as possible. Data were collected from 173 bilingual children aged 5 to 8 across three countries (France, Netherlands, UK) with various heritage languages in each. Parents completed the Q-BEx questionnaire and children proficiency tasks in their societal language. We analysed the predictive power of the original score compared to several alternative scoring approaches. Results showed (i) these alternatives were not more informative, (ii) scores including qualitative aspects of richness fared better than those with only quantitative variables, (iii) the latent variables underlying richness were comparable across languages, and (iv) whether parental education was included made little difference.

Color perception is influenced by lexical categories. Previous research shows that languages partition the color spectrum in unique ways, leading to faster discrimination between colors belonging to different categories (Kay & Kempton, 1984; Winawer et al., 2007). The influence of color names on perception in bilinguals is not conclusive. In Italian, dark and light blues are distinguished as separate categories (blu and azzurro), while French speakers use bleu for both. We tested French–Italian bilinguals in a speeded color discrimination task, where language was indirectly involved, and compared the results with monolingual controls. Bilinguals tended to align with Italian monolinguals, as Italian categories dominated their perception of blue hues, but also showed some French-like behavior, reflecting the stability of the dark blue category. Bilinguals, therefore, process color through a mix of both languages, suggesting that language plays a key role in bilingual cognition, whose perception is shaped by more complex processes.

This study examines the underlying mechanisms driving the bilingual advantage in learning English as a foreign language (EFL) among kindergarten-aged children. Participants included 85 Dutch-speaking monolinguals and 34 bilingual children. We assessed children’s English vocabulary and grammar as the outcome variables. Furthermore, phonological awareness, executive functions and motivation to learn English were measured as potential mediators of the bilingualism–EFL relationship. We also controlled for child age, non-verbal IQ, Dutch (majority language) proficiency, intensity of school English instruction, parental education and exposure to English activities. Results showed that bilingual children outperformed monolinguals in English receptive vocabulary, but only for noncognate words; no differences emerged for cognate words or English grammar. However, none of the proposed mediators explained this advantage. Findings are discussed in terms of why the effect was limited to vocabulary and potential alternative mechanisms not explored in the present study.

Previous work had shown that multilingual preschool children are better at interpreting deictic gestures than their monolingual peers. The present study examines whether this multilingual effect persists beyond preschool age and whether it extends to iconic (i.e., representing the referent) and conventional (i.e., holding an arbitrary meaning) gestures. A total of N = 105 children (aged 3 to 8), varying in their balance of exposure to more than one language since birth, completed a gamified gesture comprehension task. The three gesture types were presented in four communicative conditions, namely (1) alone, with (2) reinforcing or (3) supplementing speech, compared to (4) speech produced alone. Analyses revealed that children with greater balance in their multilingual exposure understood significantly more speechless iconic gestures than children with less balanced multilingual exposure. Findings align with previous work and theoretical frameworks, indicating that multilingual exposure enhances children’s sensitivity to non-verbal communicative cues.