Previous research has shown that non-Māori Speaking New Zealanders have extensive latent knowledge of Māori, despite not being able to speak it. This knowledge plausibly derives from a memory store of Māori forms (Oh et al., 2020; Panther et al., 2023). Modelling suggests that this ‘proto-lexicon’ includes not only Māori words, but also word-parts; however, this suggestion has not yet been tested experimentally.

We present the results of a new experiment in which non-Māori speaking New Zealanders and non-New Zealanders were asked to segment a range of Māori words into parts. We show that the degree to which segmentations of non-Māori speakers correlate to the segmentations of two fluent speakers of Māori is stronger among New Zealanders than non-New Zealanders. This research adds to the growing evidence that even in a largely ‘monolingual’ population, there is evidence of latent bilingualism through long-term exposure to a second language.

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.

The aim of the study is to explore the differential effects of neurodegenerative disorders on cross-language interference and facilitation, by comparing the performance in a bilingual Stroop task of Catalan–Spanish bilinguals with different neurodegenerative disorders [Mild Cognitive Impairment (MCI), n = 16; Alzheimer's disease (AD), n = 16; and Parkinson's disease (PD), n = 16)] and healthy controls (n = 14). Interference is the difference in naming latencies between the incongruent (colour words not matching with their ink colour) and control (non-colour words) conditions. Facilitation is the difference between the control and congruent conditions (colour words matching with their ink colour).

The results showed that AD and MCI patients, but not PD, showed a larger interference effect than healthy controls. Nevertheless, the patient groups showed the same facilitation effect as healthy controls.

The contribution of cortical and subcortical brain areas to cross-language interference suppression is discussed in relation to the type of brain degeneration.

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.

Bilinguals experience processing costs when comprehending code-switches, yet the magnitude of the cost fluctuates depending on numerous factors. We tested whether switch costs vary based on the frequency of different types of code-switches, as estimated from natural corpora of bilingual speech and text. Spanish–English bilinguals in the U.S. read single-language and code-switched sentences in a self-paced task. Sentence regions containing code-switches were read more slowly than single-language control regions, consistent with the idea that integrating a code-switch poses a processing challenge. Crucially, more frequent code-switches elicited significantly smaller costs both within and across most classes of switch types (e.g., within verb phrases and when comparing switches at verb-phrase and noun-phrase sites). The results suggest that, in addition to learning distributions of syntactic and semantic patterns, bilinguals develop finely tuned expectations about code-switching behavior – representing one reason why code-switching in naturalistic contexts may not be particularly costly.

In adulthood, novel words are commonly encountered in the context of sequential language learning, and to a lesser extent, when learning a new word in one's native language. Paired-associate (PAL) and cross-situational word learning (CSWL) paradigms have been studied separately, under distinct theoretical umbrellas, limiting the understanding of the mechanisms underlying the learning process in each. We tested 126 monolinguals and 111 bilinguals on PAL and CSWL, manipulating familiarity and measuring verbal working memory. Results revealed highly similar learning performance across groups, both demonstrating better performance in PAL than in CSWL, similar sensitivity to familiarity, and similar reliance on phonological working memory. We observed a trend such that bilinguals outperformed monolinguals in PAL but not in CSWL, but this trend was weak. Findings indicate limited effects of bilingualism on word learning in adulthood and suggest highly similar word learning mechanisms in learners with different linguistic experiences.

Semantic feature-based treatments (SFTs) are effective rehabilitation strategies for word retrieval deficits in bilinguals with aphasia (BWA). However, few studies have prospectively evaluated the effects of key parameters of these interventions on treatment outcomes. This study examined the influence of intervention-level (i.e., treatment language and treatment sessions), individual-level (baseline naming severity and age), and stimulus-level (i.e., lexical frequency, phonological length, and phonological neighborhood density) factors on naming improvement in a treated and untreated language for 34 Spanish–English BWA who completed 40 hours of SFT. Results revealed significant improvement over time in both languages. In the treated language, individuals who received therapy in their L1 improved more. Additionally, higher pre-treatment naming scores predicted greater response to treatment. Finally, a frequency effect on baseline naming accuracy and phonological effects on accuracy over time were associated with differential treatment gains. These findings indicate that multilevel factors are influential predictors of bilingual treatment outcomes.

Bilingualism has been shown to contribute to increased resilience against cognitive aging. One of the key brain structures linked to memory and dementia symptom onset, the hippocampus, has been observed to adapt in response to bilingual experience – at least in healthy individuals. However, in the context of neurodegenerative pathology, it is yet unclear what role previous bilingual experience might have in terms of sustaining integrity of this structure or related behavioral correlates. The present study adds to the limited cohort of research on the effects of bilingualism on neurocognitive outcomes in Mild Cognitive Impairment (MCI) using structural brain data. We investigate whether bilingual language experience (operationalized as language entropy) results in graded neurocognitive adaptations within a cohort of bilinguals diagnosed with MCI. Results reveal a non-linear effect of bilingual language entropy on hippocampal volume, although they do not predict episodic memory performance, nor age of MCI diagnosis.

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.

Bilingualism is thought to confer advantages in executive functioning, thereby contributing to cognitive reserve and a later age of dementia symptom onset. While the relation between bilingualism and age of onset has been explored in Alzheimer's dementia, there are few studies examining bilingualism as a contributor to cognitive reserve in frontotemporal dementia (FTD). In line with previous findings, we hypothesized that bilinguals with behavioral variant FTD would be older at symptom onset compared to monolinguals, but that no such effect would be found in patients with nonfluent/agrammatic variant primary progressive aphasia (PPA) or semantic variant PPA. Contrary to our hypothesis, we found no significant difference in age at symptom onset between monolingual and bilingual speakers within any of the FTD variants, and there were no notable differences on neuropsychological measures. Overall, our results do not support a protective effect of bilingualism in patients with FTD-spectrum disease in a U.S. based cohort.

The purpose of the current report is to study the effects of language distance on noun and verb processing in bilingual speakers. We recruited two groups of bilingual speakers: one group spoke two typologically distant languages (Cantonese and English) and the other group spoke two typologically similar languages (Mandarin and Cantonese). Participants named object and action pictures in their first language. We controlled psycholinguistic properties of words such as frequency, AoA, imageability, name agreement, visual complexity, familiarity, and participants’ bilingual language experiences. Our findings revealed a significant role for language distance. We observed a difference between noun and verb processing in the similar language pair (Mandarin–Cantonese) due to interference induced by language similarity. However, in the distant language pair (Cantonese–English), the difference disappeared because of the lack of cross-language interference. Our findings support that current and future models of bilingual language processing should take into account the effects of language distance.

The umbrella term cognitive reserve-enhancing factors refers to those experiential and lifestyle factors (such as intellectual activities, regular physical exercise, healthy nutrition, educational attainment, etc.) that may help individuals to compensate for age-related neural deterioration, thus enabling them to maintain relatively stable cognitive functioning during senescence. In the last 10 years, mounting evidence has shown that speaking a second language is a powerful cognitive reserve contributor, which could mitigate the consequences of healthy aging and contribute to the delay of dementia onset. In this piece, we argue that bilingualism may play a unique role among the well-known cognitive reserve-enhancing factors, thus contributing to the achievement of successful aging in a distinctive fashion. After reviewing behavioral and neuroimaging evidence for bilingualism-induced protection against healthy and pathological cognitive aging, we discuss theoretical reasons and experimental findings supporting the view that bilingualism should be granted an individual spot among reserve-enhancing life experiences.

Bilinguals often show evidence of cross language influences, such as facilitation in processing cognates. Here we use computational methods for analyzing spontaneous English texts written by hundreds of speakers of different L1s, at different levels of English proficiency, to investigate writers’ preference for using cognates over alternative word choices. We focus on English, since a majority of its lexicon is either of Romance or Germanic origin, allowing an investigation of the preference of speakers of Germanic and Romance L1s towards cognates between their L1 and English. Results show that L2 writers tend to prefer English cognates, and that this tendency is weaker as English proficiency level increases, suggesting diminishing effects of CLI. However, a comparison of the L2 writers with native English writers shows general overuse of cognates only for the Germanic, but not the Romance, L1 speakers, most likely due to the register of argumentative writing.

Early bilingual language experience can enhance children's social-cognitive skills for effective communication. This study examined whether individual variability in bilingual language diversity, measured by language entropy, influenced 3- to 5-year-old children's engagement of contextual information in their selective trust strategies. One-hundred-and-forty Singaporean children (58 girls, Mage = 53.64 months, 97.1% Asian) were presented with an informant who provided either accurate or inaccurate information in a context with either adequate or limited information access. Bilingual children with greater language diversity, compared to those with less language diversity, were more likely to adapt their accuracy-based selective trust strategy to the informant's circumstances (i.e, information access). Results provide new insights into the role of diverse linguistic experiences in shaping children's social cognitive development.

This study investigates bilingualism-induced neuroplastic and cognitive-reserve effects in the Caudate Nucleus (CN), a structure believed to support both bilingual language control and domain-general executive functioning. We computed a generalized bilingualism index incorporating several dimensions of bilingual experience in a sample of bilingual young adults and tested whether this index would predict behavioral executive performance (measured using a Flanker task) and volumetric differences in the CN. Moreover, we investigated whether bilingualism mitigates the relationship between CN volume and executive performance, a sign of cognitive reserve. Our results indicate that bilingualism facilitates executive performance and induces an inverted U-shaped neuroplastic trajectory in bilateral CN, consistently with the view that structural increases are replaced by functional improvements as bilingual experience progresses. The emergence of bilingualism-induced cognitive reserve effects in CN further supports the view that bilinguals rely progressively less on the availability of structural resources in the face of increased functional efficiency.

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.

In this behavioral and electrophysiological study, we compare novel word learning, particularly lexical form acquisition, in an immersive virtual reality (VR) context with a picture-word (PW) association context. We also test whether inhibitory control and age of second language acquisition (L2 AoA) have modulating effects. Chinese speakers of L2 English learned two sets of German words, one set in each of the contexts. Behavioral performance from a subsequent recognition task indicated that responses to VR-learned words were faster than PW-leaned words. ERPs revealed that VR-learned words elicited more negative N100 and N200 waveforms than PW-learned words. Moreover, a significant relationship between L2 AoA and N200 amplitude was observed for VR-learned words. Taken together, the results suggest that the multi-sensory, interactive experience simulated by an immersive VR context has a positive effect on early lexical form acquisition of novel words.

This study investigated the engagement of domain-general cognitive control during the comprehension of dense code-switching sentences. Stimulus-locked event-related potentials (ERPs) were measured while L1-dominant Chinese–English bilinguals read switch and non-switch sentences. The results of the reading task revealed language dominance effects on the N400, left anterior negativity (LAN) and late positive component (LPC). The language dominance effects at lexical level (i.e., on the N400 and LAN) were modulated by individual differences in monitoring capacity. In contrast, inhibition capacity predicted code-switching costs at the sentence level (i.e., for the LPC component). The results suggest that proactive monitoring and reactive inhibition affect different processing stages during the comprehension of dense code-switching sentences. These findings partially align with processing models of code-switching incorporating a dual control mode perspective and contribute new insight into the dynamic interplay between reactive and proactive control processes.

We examined moral judgments in three types of language: a native national language (Italian), a non-native foreign language (English), and a native regional language (Venetian, oral and colloquial). We used the Moral Foundation Questionnaire to investigate cross-linguistic differences in multiple aspects of morality. Higher scores in the Harm, Purity and Fairness dimensions were obtained in the foreign and the regional language with respect to the national language. In addition, higher scores in the Ingroup dimension were obtained in the foreign language with respect to the native language. The effects of language on morality can thus be quite pervasive, involving a variety of aspects of morality. The differences we observed across these languages are explained in terms of their sociolinguistics – specifically, the greater use of national languages with moral values and beliefs. It is proposed that language effects arise because the language that is used activates information associated with it.