Monolingual children tend to assume that a word labels only one object, and this mutual exclusivity supports referent selection and retention of novel words. Bilingual children accept two labels for an object (lexical overlap) for referent selection more than monolingual children, but in these previous studies, information about speakers’ language backgrounds was minimal. We investigated monolingual and bilingual 4-year-old children’s ability to apply mutual exclusivity and lexical overlap flexibly when objects were labelled either by one or two speakers with the same or different language backgrounds. We tested referent selection and retention of word–object mappings. Both language groups performed similarly for mutual exclusivity, were more likely to accept lexical overlap in the two-language than one-language condition, and performance was similar for referent selection and later retention. Monolingual and bilingual children can adapt their word-learning strategies to cope with the demands of different linguistic contexts.

Previous research has demonstrated that predictable words that are not presented linger in memory and lead to false recognition in subsequent memory tests. However, little is known about these effects among second language learners, a population that is known for engaging less in prediction. Here, we used a self-paced reading and word recognition memory test to examine encoding differences and subsequent memory effects in groups of L1 and L2 speakers of German. For initial reading, results showed no group differences in the size of the predictability effect, possibly because group differences in attention allocation during reading masked predictability effects. For recognition memory, L2 learners showed reduced rates of false remembering for predictable words (after correcting for response bias), and they were also less likely to false-alarm to predictable words with high subjective memory confidence, similar to L1 speakers. In addition, L2 learners showed reduced recognition memory for previously presented words. Taken together, these results are consistent with models arguing that lexical-semantic entries are less firmly represented in the L2 lexicon, which in turn lowers pre-activation of predictable referents during L2 sentence processing and leads to the formation of less distinct memory representations for previously encoded information.

We investigate timing and eye-movement behavior during semantic prediction in L1 and L2 speakers of English using the Visual World Paradigm, additionally exploring speech rate. We differentiate first-stage predictions, considered to be automatic and relatively cost-free, from second-stage predictions, which are non-automatic and more cognitively demanding, with differences between L1 and L2 speakers believed to arise in second-stage predictions. We found no differences in the divergence of looks to the target in first- or second-stage predictions across groups. However, speech rate played an important role. Both L1 and L2 speakers showed similar first-stage predictions at slower speech rates, but L1 speakers showed earlier predictions as the speech rate increased. L2 speakers showed reduced and more variable second-stage predictions, suggesting they were impacted during the more demanding second-stage prediction. This may indicate a wait-and-see strategy to help reduce costs associated with second-stage prediction.

Learning to map novel words onto their intended referents is a complex challenge, and one that becomes even harder when acquiring multiple languages. We investigated how label mixing affected learning novel words in one versus two languages. In a cross-situational word learning study, 80 adult participants learned either one-to-one word–object mappings, or two-to-one mappings, reflecting different challenges in learning one or two languages. We manipulated whether mappings co-occurred locally, where repetitions were prevalent, or whether co-occurrences were more distributed throughout exposure. Learners acquired two-to-one mappings better when they did not occur in local co-occurrences, but there was no effect of learning conditions for one-to-one mappings. Whether participants were proficient or not in an additional language did not have an observable effect on the learning. We suggest that local co-occurrences of multiple labels, as in language mixing environments, increase the challenge of learning words, though this effect may be only short-lived.

Embodied cognition theory posits that language comprehension is grounded in sensorimotor experience. For instance, abstract concepts such as perceived power are metaphorically associated with spatial information such as physical size. Here, using a size judgement task, we investigated whether perceived power embodiment differs between languages in Chinese–English bilinguals. Asked to make judgements regarding the physical size of words, participants responded faster and made fewer errors to high-power words (e.g., king) presented in bold and large font than in thin and small font, while no such effect was found for low-power words. Furthermore, this congruency effect was stronger in bilinguals’ L1 (Chinese) than in their L2 (English). Thus, while embodiment of perceived power is detectable in both languages of bilinguals, it appears weaker in the L2. This study highlights cross-linguistic similarities and differences in the embodiment of abstract concepts and contributes to our understanding of conceptual knowledge grounding in bilinguals.

Whether bilingualism confers non-linguistic cognitive advantages continues to generate both interest and debate in the psychological sciences. In response to mixed reports and methodological critiques, researchers have embraced more rigorous practices when investigating bilingual effects, including those in the domain of cognitive control. Despite considerable advances, one significant issue persists: the assumption that task performance remains stable over time. To address this, the present study investigated the relationship between bilingual language experience and Simon task performance modeled as a continuous function of time. In a sample of Mandarin-English bilingual young adults, we identified distinct patterns of results across both conventional and time-sensitive performance trajectory measures with each supporting a different relationship between language experience and cognitive control. Results suggest that reliance on conventional performance measures may be partially responsible for mixed results, necessitating reevaluation of how bilingual effects on cognitive control manifest and which analysis methods best support their identification.

Bilinguals simultaneously activate both languages during word retrieval. False cognates, words overlapping in form but not meaning across languages, typically trigger crosslinguistic interference relative to non-cognates. Crosslinguistic interference resolution can be impaired in bilinguals with stroke-induced aphasia, yet little is known about the neural dynamics supporting these interference resolution processes. We recorded scalp electroencephalography in 21 age-matched controls and five bilinguals with aphasia participating in a picture-word interference paradigm eliciting crosslinguistic interference and a nonlinguistic spatial Stroop task. Bilinguals with aphasia showed lower performance than age-matched controls and crosslinguistic interference was present across both groups. A medial frontal component peaking around 400 ms post stimulus presentation was present in controls across tasks but was absent in the linguistic task in bilinguals with aphasia. This suggests that while bilinguals typically engage the medial frontal cortex to resolve crosslinguistic interference, this mechanism is disrupted in bilinguals with aphasia.

We corroborate findings showing a disparity in one’s willingness to update political beliefs in the face of counterevidence among bilinguals, examining the role of the Foreign Language effect (FLe) on belief maintenance. 133 Liberal English-Spanish bilinguals and 70 English monolinguals showed that belief change on political issues is lesser than on nonpolitical issues following counterevidence. Bilinguals, however, showed greater change in the second language (L2) compared to the first and greater belief change than the monolinguals overall. The second language also led to slower reading and rating times across all conditions, which corresponded with greater belief change. Among bilinguals using their L2, those most likely to show belief change reported having a less meaningful connection to the foreign language.

Past research suggests that novel word learning is facilitated by multimodal contexts, which enrich semantic representations and strengthen memory traces. We explored whether environmental sounds (e.g., a creaking door) facilitate foreign language (FL) word learning. In all, 36 Spanish-speaking natives learned 60 written Spanish–FL word pairs, each accompanied by one of three sound conditions: a congruent sound matching the word pairs’ denotation, a meaningless tone or silence. Participants then completed a semantic priming and lexical decision task where reaction times and accuracy were collected. Performance was similar for congruent sound and tone conditions and, compared to silence, showed lower accuracy in the lexical decision task and a marginal benefit in the semantic task. These findings suggest that environmental sounds can influence learning, with varying effects depending on the task. Results are discussed in terms of current language learning models.

People’s decisions may change when made in a foreign language (FL). Research testing this foreign language effect (FLE) has mostly used scenarios where uncertainty is expunged or reduced to a form of risk, whereas real-life decisions are usually characterized by uncertainty around outcome likelihood. In the current work, we aimed to investigate whether the FLE on decision-making extends to uncertain scenarios. Moreover, as it is still unclear what linguistic and psychological factors contribute to the FLE, we tested the effects of participants’ FL background, cognitive style and risk-taking attitude on decision processes under certain and uncertain conditions. Overall, we report null effects of language context (native versus foreign language) and problem condition (certain versus uncertain prospects) on participants’ choices. In addition, we found that both FL background and decision makers’ traits modulated participants’ choices in a FL, without emerging into the ‘classic’ FLE on decision-making. However, the direction of such effects was complex, and not always compatible with previous FLE theories. In light of these results, our study highlights the need to reconceptualize the FLE and its implications on decision-making.

We investigated the interactive effects of bilingualism and sleep on executive functioning at the behavioral level. We conducted two experiments using two independent samples of bilingual young adults, the Flanker task to assess executive performance, the Pittsburg Sleep Quality Index to measure retrospective sleep quality over a one-month period and the Insomnia Severity Index to assess insomnia-related symptoms. In Experiment 1, we registered bilingualism effects on executive performance in poor, but not in good sleepers. In Experiment 2, the magnitude of bilingual effects increased with increasing severity of insomnia symptoms. We conclude that when poor sleep quality and insomnia negatively affect cognitive resources, bilingualism-related cognitive effects emerge more prominently. This suggests higher degrees of bilingualism may compensate detrimental effects of poor sleep quality and insomnia on executive functioning. We suggest that cognitive research in bilingualism and sleep could benefit from controlling for interindividual variability in sleep quality and vice versa.

Exposure to multiple languages may support the development of Theory of Mind (ToM) in neurotypical (NT) and autistic children. However, previous research mainly applied group comparisons between monolingual and bilingual children, and the underlying mechanism of the observed difference remains unclear. The present study, therefore, sheds light on the effect of bilingualism on ToM in both NT and autistic children by measuring language experiences with a continuous operationalization. We measure ToM with a behavioral, linguistically simple tablet-based task, allowing inclusive assessment in autistic children. Analyses revealed no difference between monolingual and bilingual NT and autistic children. However, more balanced exposure to different languages within contexts positively predicted first-order false belief understanding in NT children but not autistic children. Mediation analysis showed that the impact in NT children was a direct effect and not mediated via other cognitive skills.

Recent studies showed contradictory results with regard to the implementation of proactive language control during bilingual sentence production. To add novel evidence to this debate, the current study investigated the blocked language order effect, a measure of proactive language control that has previously only been examined in single-word production. More specifically, bilingual participants completed a network description task, using their L1 in Blocks 1 and 3 and their L2 in Block 2. Results showed increased language intrusions in Block 3 compared to Block 1. This pattern indicates that proactive language control can be implemented during bilingual sentence production.

Early language development has rarely been studied in hearing children with deaf parents who are exposed to both a spoken and a signed language (bimodal bilinguals). This study presents longitudinal data of early communication and vocabulary development in a group of 31 hearing infants exposed to British Sign Language (BSL) and spoken English, at 6 months, 15 months, 24 months and 7 years, in comparison with monolinguals (exposed to English) and unimodal bilinguals (exposed to two spoken languages). No differences were observed in early communication or vocabulary development between bimodal bilinguals and monolinguals, but greater early communicative skills in infancy were found in bimodal bilinguals compared to unimodal bilinguals. Within the bimodal bilingual group, BSL and English vocabulary sizes were positively related. These data provide a healthy picture of early language acquisition in those learning a spoken and signed language simultaneously from birth.