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).

Titone and Tiv's Systems Theory of Bilingualism aims to “urge cognitive scientists and neuroscientists to better embrace sociolinguistic and sociocultural experiences as part of their theoretical and empirical purview”. No stronger case for such a framework can be found than in studies of developmental aspects of bilingualism. In fact, inclusion of sociocultural variation has been a common feature of many studies of dual language learning for some time, especially in studies of pre-school and early-school-age learners (see Genesee, 2019, for a review). Young dual language learners – neonates, infants and toddlers, exposed to more than one language – begin life as virtual tabula rasa and are capable of learning any language with facility. As a result, their language acquisition is necessarily tied to the sociocultural parameters of the learning environments they are exposed to. Moreover, as Titone and Tiv emphasize, the immediate and ultimate purpose of language learning is communication. Thus, young dual language learners must be attuned to and acquire the sociocultural constraints and norms for communicating effectively in more than one language. While sociocultural variation is important for understanding language acquisition even among monolingual children living in relatively homogeneous monocultural environments, sociocultural variation is inherent and, indeed, enhanced in the learning environments of children acquiring more than one language insofar as each language is intimately linked with different socio-cultural parameters. Sociocultural variation can be important for understanding bilingualism in yet another way. In studies of the neuro-cognitive consequences of bilingualism, it has been reported that there is a more pronounced association between dual language exposure and activation of certain brain areas among adolescent bilinguals from relatively low SES backgrounds than bilinguals from relatively high SES backgrounds (Brito & Noble, 2018). Inclusion of sociocultural variation in research on the effects of bilingualism can reveal a more nuanced view than emerges if such variation is not considered.

Drawing on the adaptive control hypothesis, we examined whether older adults’ bilingual interactional contexts of conversational exchanges would predict important indices of executive functions (EF). We assessed participants’ engagement in each bilingual interactional context – single-language, dual-language, and dense code-switching – and their performance on a series of nonverbal EF measures. Sixty-nine healthy older adults (Mage = 70.39 years; ages 60–93) were recruited from local community centers. We found that the dense code-switching context was associated with enhanced overall EF, but not individual facets of EF (inhibitory control, shifting, and updating). These findings held true when we controlled for a host of covariates. Our findings shed light on aging bilinguals’ interactional contexts as crucial bilingual experiences that modulate overall EF. Given that bilingualism is a multidimensional construct, rather than a unidimensional variable, our study underscores the importance of more fine-grained operationalisation of bilingualism when studying its impacts on EF.

We investigated cross-modal influences between speech and sign in hearing bimodal bilinguals, proficient in a spoken and a sign language, and its consequences on visual attention during message preparation using eye-tracking. We focused on spatial expressions in which sign languages, unlike spoken languages, have a modality-driven preference to mention grounds (big objects) prior to figures (smaller objects). We compared hearing bimodal bilinguals’ spatial expressions and visual attention in Dutch and Dutch Sign Language (N = 18) to those of their hearing non-signing (N = 20) and deaf signing peers (N = 18). In speech, hearing bimodal bilinguals expressed more ground-first descriptions and fixated grounds more than hearing non-signers, showing influence from sign. In sign, they used as many ground-first descriptions as deaf signers and fixated grounds equally often, demonstrating no influence from speech. Cross-linguistic influence of word order preference and visual attention in hearing bimodal bilinguals appears to be one-directional modulated by modality-driven differences.

This study investigated whether the deployment of cognitive control was modulated by the intra-sentential code-switching types during comprehension. L1-dominant Chinese–English bilinguals were administered a self-paced reading task in two reading contexts – namely, alternation context and dense code-switching context. We assessed language switch cost and reversed language dominance effect in the self-paced reading task and examined how these language control measures related to domain-general inhibition and monitoring capacities. The results showed a larger switch cost asymmetry in alternation context compared to dense CS context. In addition, bilinguals’ inhibition skills were associated with second language (L2) switch cost in alternation context, while monitoring tended to predict the language dominance effect in dense code-switching context. These findings suggest that alternation context exerts high requirement to reactive inhibition while dense code-switching context tends to induce proactive monitoring during comprehension. We conclude that intra-sentential code-switching types trigger different aspects of cognitive control during comprehension.

Findings of bilingual participants outperforming their monolingual counterparts in executive functioning tasks have been repeatedly reported in the literature (Bialystok, 2017). However, uncontrolled factors or imperfectly matched samples might affect the reliability of these findings. This study aims to take into account a range of relevant variables in combination with innovative analyses to investigate the performance of one unstudied language group, Greek–English bilingual children in the north of England, compared to monolingual control groups. Our battery of executive function tasks taps into inhibition, updating and shifting. We use k-means nearest neighbour methods to match the groups and factor analysis to determine language proficiency. We find that bilinguals’ accuracy is on a par with their monolingual peers – however, they are faster in inhibition and working memory tasks. Our study provides strong evidence for the presence of a bilingual advantage in these domains, while making important methodological contributions to the field.

Understanding jokes may differ between mono- and bilinguals because of differences in lexical access; fluency and sense of humor may also be relevant. Three experiments examined English-language joke comprehension in monolingual (n = 91) and bilingual (n = 111) undergraduates, Russian–English bilinguals (n = 39), and MTurk monolinguals (n = 77). Participants rated jokes and non-jokes in English as funny or not funny. We assessed the effects of bilingualism, language dominance, fluency, sense of humor, experience, and motivation on response time (RT) and sensitivity (d′) in identifying jokes. Bilingualism predicted neither RT nor d′ in mono- and English-dominant bilingual undergraduates; English fluency predicted d′. Russians were slower than English-dominant bilinguals but were more not less sensitive to humor. MTurk monolinguals were faster than undergraduates and equally sensitive; sense of humor predicted sensitivity. Overall, humor processing is alternately affected by fluency, sense of humor, and motivation, depending on the population. Bilingualism per se is not a factor.

While most investigations of bilingualism document participants’ language background, there is an absence of consensus on how to quantify bilingualism. The high number of different language background questionnaires used by researchers and practitioners jeopardises data comparability and cross-pollination between research and practice. Using the Delphi consensus survey method, we asked 132 panellists (researchers, speech and language therapists, teachers) from 29 countries to rate 124 statements on a 5-point agreement scale. Consensus was pre-defined as 75% agreement threshold. After two survey rounds, 79% of statements reached consensus. The need for common measures to quantify bilingualism was acknowledged by 96% of respondents. Agreement was reached to document: language exposure and use, language difficulties, proficiency (when it cannot be assessed directly), education and literacy, input quality, language mixing practices, and attitudes (towards languages and language mixing). We discuss the implications of these findings for the creation of a new tool to quantify bilingual experience.

Bilinguals’ emotions can vary in intensity with the language of a stimulus. Yet, extant research has somewhat surprisingly accepted inconsistent results from implicit nonverbal and explicit verbal emotion measures. To date, it is unclear if this inconsistency recurs to conceptual or methodological differences. We therefore investigated if squeezing a handheld dynamometer is a valid nonverbal, “visceral” alternative to self-reported language-dependent feelings by comparing explicit ratings to neuro-physiological emotional reactions. We replicated two pupillometry experiments inducing language-dependent emotions through sentence reading (Study 1) and listening to narrative video commercials (Study 2) of low and high emotionality in the first or second language. Pupillometry confirmed that bilinguals are more sensitive to the low-high emotionality contrast in their first than second language. Grip force (but not duration) mirrored these findings, whereas verbal ratings did not. We thus recommend grip force as a new attentional, nonverbal measure for bilingualism research.

Morphological awareness contributes to vocabulary acquisition and reading in bilingual children who learned English after their native language. In line with these considerations, we further investigated L2 processing in late adult bilinguals where questions related to morphology need to be clarified. French–English speakers (N = 92) were assessed for three morphological awareness stages: lexical semantic knowledge, syntactic knowledge, and distributive knowledge. We investigated whether the evolution of morphological awareness was related to L2 proficiency and whether it was facilitated by the presence of suffixes shared in L1 and L2. Our results confirmed the influence of language proficiency at each stage of morphological awareness. However, the hypothesis of an advantage of suffixes shared between French and English was not confirmed as no clear advantage was found for those suffixes. Our findings are discussed in line with the morphological congruence hypothesis and compared with the previous results in the literature.

It is well-known that native English speakers sometimes erroneously accept subject-verb agreement violations when there is a number-matching attractor (e.g., *The key to the cabinets were…). Whether bilinguals whose L1 lacks number agreement are prone to such interference is unclear, given previous studies that report conflicting findings using different structures, participant groups, and experimental designs. To resolve the conflict, we examined highly proficient Korean–English bilinguals’ susceptibility to agreement attraction, comparing prepositional phrase (PP) and relative clause (RC) modifiers in a speeded acceptability judgment task and a speeded forced-choice comprehension task. The bilinguals’ judgments revealed attraction with RCs but not with PPs, while reaction times indicated attraction with both structures. The results therefore showed L2 attraction in all measures, with the consistent exception of judgments for PPs. We argue that this supports an overall native-like agreement processing mechanism, augmented by an additional monitoring mechanism that filters explicit judgments in simple structures.

Both inhibitory control and typological similarity between two languages feature frequently in current research on multilingual cognitive processing mechanisms. Yet, the modulatory effect of speaking two typologically highly similar languages on inhibitory control performance remains largely unexplored. However, this is a critical issue because it speaks directly to the organisation of the multilingual's cognitive architecture. In this study, we examined the influence of typological similarity on inhibitory control performance via a spatial Stroop paradigm in native Italian and native Dutch late learners of Spanish. Contrary to our hypothesis, we did not find evidence for a differential Stroop effect size for the typologically similar group (Italian–Spanish) compared to the typologically dissimilar group (Dutch–Spanish). Our results therefore suggest a limited influence of typological similarity on inhibitory control performance. The study has critical implications for characterising inhibitory control processes in multilinguals.

Several studies on heritage language (HL) acquisition investigate a single linguistic structure, showing how language exposure or cross-linguistic effects affect its acquisition. Here, we consider HL speaking children's mastery of several linguistic structures using a cloze-test. We examine how their language competence is affected by language exposure variables and age. We tested 180 children between the ages of 8 and 16, living in Switzerland and speaking European Portuguese as HL and French, German or Italian as their societal language. The items of the cloze-test cluster around two levels of difficulty, with the items at the second level corresponding to structures that are acquired late in Portuguese monolingual acquisition. Older age and a greater amount of formal instruction in the HL lead to better performance. The role of the amount of formal instruction varies based on the level of difficulty of the target structures. Cross-linguistic influence does not affect the results.

This study investigated the effect of external non-linguistic cues on language selection in bilinguals. Participants viewed photographs and stated in which language they would speak to the individuals in those photographs via a button press. These images were manipulated such that external cues (the ‘speak Welsh’ logo, presented in the form of a poster or a lanyard) were present or absent. Participants responded faster and selected Welsh as their language of choice more often in trials that contained a language cue than in trials in which a language cue was absent. Furthermore, trials containing a lanyard had a greater effect on participant performance than trials containing a poster. These results suggest that external cues can influence language selection in bilinguals, and that the perceived reliability of the cue can modulate this effect. These findings have implications for the language selection literature and could inform the development of future language use interventions.