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.

To become fluent in a second language, learners need to acquire a large vocabulary. However, the cognitive and affective mechanisms that support word learning, particularly among second language learners, are only beginning to be understood. Prior research has focused on intentional learning and small artificial lexicons. In the current study investigating the sources of individual variability in word learning and their underlying mechanisms, participants intentionally and incidentally learned a large vocabulary of Welsh words (i.e., emulating word learning in the wild) and completed a large battery of cognitive and affective measures. The results showed that, for both learning conditions, native language knowledge, auditory/phonological abilities and orthographic sensitivity all made unique contributions to word learning. Importantly, short-term/working memory played a significantly larger role in intentional learning. We discuss these results in the context of the mechanisms that support both native and non-native language learning.

This study investigated how natural language use influences inhibition in language-unbalanced bilinguals. We experimentally induced natural patterns of language use (as proposed by the Adaptive Control Hypothesis) and assessed their cognitive after-effects in a group of 32 Polish–English bilinguals. Each participant took part in a series of three language games involving real conversation. Each game was followed by two inhibition tasks (stop-signal task and Stroop task). The manipulation of language use in the form of language games did not affect the behavioural measures, but it did affect ERPs. Performance of the inhibition tasks was accompanied by a reduction of P3 and the N450 amplitude differences after games involving the use of L2. The ERP modulations suggest that for bilinguals living in an L1 context the use of L2 enhances neural mechanisms related to inhibition. The study provides the first evidence for a direct influence of natural language use on inhibition.

Many language pairs chosen in language switching studies differ randomly on multiple linguistic levels, thus obscuring the nature of switching costs. Contact-induced languages, i.e., creoles (e.g., Spanish-based Palenquero) and mixed languages (e.g., Media Lengua), having arisen in intense language contact scenarios, relate systematically to their source languages by displaying high proportions of cognates or shared grammar. This configuration can speak to the relative contribution of lexicon and grammar to switching costs. Results from a production and comprehension task show that switching costs are systematically tied to a language pair's grammatical distance. This suggests that switching costs may result from the re-generation of the morphosyntactic frame on switch trials. Emphasizing the value of testing psycholinguistic theories outside of the usual Western populations, the current study provides insight into the degree of shared mental representations between contact-induced languages and their source languages.

The question of interest in this study was whether bilingual individuals show superior executive control compared to monolingual participants. Findings are mixed, with studies showing advantage, disadvantage, or no difference between bilingual and monolingual speakers. In this study, we used different experimental conditions to examine implicit learning, resistance to interference, monitoring, and switching, independently. In addition, we matched our monolingual and bilingual participants on baseline response time. Bilingual participants demonstrated faster implicit learning, greater resistance to interference, more efficient switching compared to monolingual participants. The groups did not differ in monitoring. In conclusion, depending on task complexity and on the target executive control component, there are different patterns of bilingual advantage, beyond the global faster processing speed documented in previous studies. Bilingual young adults showed more efficient adjustments of the cognitive system in response to changes in task demands.

Multilink developed by Dijkstra et al. (2018) is a computational model of monolingual and bilingual lexical access in comprehension and production. The non-selective activation of a bilingual's two languages is handled in the model by assuming that bilinguals have an integrated lexicon and that orthographic overlap between the input and the lexical representation drives lexical activation. Hence, an orthographic unit such as the letter T may activate words from multiple languages that contain the letter, resulting in simultaneous activation of multiple languages. This basic mechanism for explaining non-selective activation is similar between Multilink and its predecessors BIA and BIA+.

Comprehenders predict what a speaker is likely to say when listening to non-native (L2) and native (L1) utterances. But what are the characteristics of L2 prediction, and how does it relate to L1 prediction? We addressed this question in a visual-world eye-tracking experiment, which tested when L2 English comprehenders integrated perspective into their predictions. Male and female participants listened to male and female speakers producing sentences (e.g., I would like to wear the nice…) about stereotypically masculine (target: tie; distractor: drill) and feminine (target: dress; distractor: hairdryer) objects. Participants predicted associatively, fixating objects semantically associated with critical verbs (here, the tie and the dress). They also predicted stereotypically consistent objects (e.g., the tie rather than the dress, given the male speaker). Consistent predictions were made later than associative predictions, and were delayed for L2 speakers relative to L1 speakers. These findings suggest prediction involves both automatic and non-automatic stages.

The term ‘metalinguistic’ is used to define the kind of ability whereby people for various purposes view language as an object. It is strongly associated with consciousness and touches on many aspects of literacy, multilingualism and language acquisition. Discussions in the research literature have generally been on specific aspects of metalinguistic knowledge: the time is ripe for a more fundamental reassessment focusing on how exactly metalinguistic ability is represented and processed on line, and how it fits in with other kinds of representation and processing. To this end, a particular theoretical perspective that takes into account contemporary research in cognitive science, the Modular Cognition Framework, will be applied with the aim of supporting further empirical investigations into this area of language ability and locating it within an integrated approach to cognition in general. Finally, the usefulness of metalinguistic knowledge will be briefly considered.

The keynote article (Mayberry & Kluender, 2017) makes an important contribution to questions concerning the existence and characteristics of sensitive periods in language acquisition. Specifically, by comparing groups of non-native L1 and L2 signers, the authors have been able to ingeniously disentangle the effects of maturation from those of early language exposure. Based on L1 versus L2 contrasts, the paper convincingly argues that L2 learning is a “less clear test” of sensitive periods. Nevertheless, we believe Mayberry and Kluender underestimate the evidence for maturational factors in L2 learning, especially that coming from recent research.

Code-mixing (CM) is a striking example of how two languages are active simultaneously in bilingual production. Gradient Symbolic Computation (GSC) proposes a formalism to account for the systematicity of CM patterns by integrating psycholinguistic notions of bilingual co-activation with generativist accounts of grammar. We applaud the attempt to bridge research traditions and all efforts to capture the systematicity of variation, and the interaction between processing and grammatical constraints in bilingual production. However, the descriptive and predictive scope of the current proposal remains somewhat unclear, as does its connection to existing accounts.

The findings for adverbs and adverbial phrases in a naturalistic corpus of Miami Haitian Creole–English code-switching show that one language, Haitian Creole, asymmetrically supplies the grammatical frame while the other language, English, asymmetrically supplies mixed lexical categories like adverbs. Traces of code-switching with an English frame and Haitian Creole lexical categories suggest that code-switching is abstractly BIDIRECTIONAL. A quantitative methodology that codes the language-indexation of the token in addition to the surrounding lexical items was used for all mixed (e.g. xYx/yXy, xYy/yXx, yYx/xXy) and unmixed (xXx/yYy) adverbs. Discourse position, especially the left-periphery, is found to be a significant factor in adverb code-switching. Sociolinguistic and psycholinguistic analyses which acknowledge the ‘low’ status of one language and the ‘high’ status of the other explain better the frequency of mixed English adverbs in a Haitian Creole frame and the rarity of mixed Haitian Creole adverbs in an English frame than a minimalist approach, such as MacSwan's (1999 and subsequent work), which uses phi-feature valuation and entails asymmetry without bidirectionality. While I provide confirmation for Myers-Scotton's (1993) Matrix Language Frame approach, I emphasize that trace bidirectional data need to be accounted for by a theory that is grounded in the sociolinguistic and psycholinguistic realities.

When people interact, aspects of their speech and language patterns often converge in interactions involving one or more languages. Most studies of speech convergence in conversations have examined monolingual interactions, whereas most studies of bilingual speech convergence have examined spoken responses to prompts. However, it is not uncommon in multilingual communities to converse in two languages, where each speaker primarily produces only one of the two languages. The present study examined complexity matching and lexical matching as two measures of speech convergence in conversations spoken in English, Spanish, or both languages. Complexity matching measured convergence in the hierarchical timing of speech, and lexical matching measured convergence in the frequency distributions of lemmas produced. Both types of matching were found equally in all three language conditions. Taken together, the results indicate that convergence is robust to monolingual and bilingual interactions because it stems from basic mechanisms of coordination and communication.

Bilinguals show word use patterns in each of their languages that differ from those of monolinguals. One interpretation is that, for bilinguals, the word meanings of one language are influenced by those of the other. Another is that the cross-language influence lies in on-line processes – word retrieval probabilities or word form activation levels. To discriminate between interpretations, we asked Mandarin–English bilinguals to name household objects in their L1 and L2 via forced choice instead of free production. The options given were the monolingual-preferred choices, eliminating memory retrieval demands and keeping those words at a high level of activation. For comparison, monolinguals of each language performed the same task in their native language. Differences from monolinguals in word choice were substantially reduced, especially in L1, but bilingual patterns still showed some cross-language influence in both L1 and L2. This outcome implicates cross-language influences on both bilingual processing and meaning representations.

Manual co-speech gestures can facilitate language comprehension, but do they influence language comprehension in simultaneous interpreters, and if so, is this influence modulated by simultaneous interpreting (SI) and/or by interpreting experience? In a picture-matching task, 24 professional interpreters and 24 professional translators were exposed to utterances accompanied by semantically matching representational gestures, semantically unrelated pragmatic gestures, or no gestures while viewing passively (interpreters and translators) or during SI (interpreters only). During passive viewing, both groups were faster with semantically related than with semantically unrelated gestures. During SI, interpreters showed the same result. The results suggest that language comprehension is sensitive to the semantic relationship between speech and gesture, and facilitated when speech and gestures are semantically linked. This sensitivity is not modulated by SI or interpreting experience. Thus, despite simultaneous interpreters’ extreme language use, multimodal language processing facilitates comprehension in SI the same way as in all other language processing.

Preregistration is an open science practice that requires the specification of research hypotheses and analysis plans before the data are inspected. Here, we discuss the benefits of preregistration for hypothesis-driven, confirmatory bilingualism research. Using examples from psycholinguistics and bilingualism, we illustrate how non-peer reviewed preregistrations can serve to implement a clean distinction between hypothesis testing and data exploration. This distinction helps researchers avoid casting post-hoc hypotheses and analyses as confirmatory ones. We argue that, in keeping with current best practices in the experimental sciences, preregistration, along with sharing data and code, should be an integral part of hypothesis-driven bilingualism research.

When bilinguals name pictures while in ‘monolingual mode’, we expect that under conditions of language-constraint and no cognate facilitation, factors influencing lexical retrieval in monolinguals ought to exert similar effects on bilinguals. To this end, we carried out a L1-only naming task on early Hindi–English bilinguals. Results of linear mixed effects analysis reveal AoA, Familiarity, Image Agreement and Codability (availability of alternate names) to be the most significant predictors of lexical retrieval speed for early bilinguals, confirming our expectations. However, we report, for the first time, a by-subject variation in Codability for bilinguals. Implications of the results are discussed in the context of current theories of bilingual lexical access and competition. In preparation for this study, Hindi norms from bilinguals for items in the Snodgrass and Vanderwart set have been established, which will be of use for stimuli selection in experimental studies involving bilinguals.

A bilingual exhibits a “semantic accent” when they comprehend or use a word in one language in a way that is influenced by its translation. Semantic accents are well-captured by feature-based models: however, few studies have specifically examined the processing of features that contribute to a semantic accent. Japanese–English bilinguals and monolinguals of each language completed three feature-based tasks focusing on culture-specific semantic features. Bilinguals exhibited semantic accents in L1 and L2 in that they had stronger associations than monolinguals between the features specific to one culture and words in the other language. Within bilinguals, culture-specific features were more strongly associated with the congruent language than the incongruent language. Finally, changes in the strengths of associations between culture-specific features and words depended more on L2 cultural immersion than L2 proficiency. Semantic accents lessened in L2 and increased in L1 after many years of exposure to the L2 culture.

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.

Bilingual and monolingual children might have different styles of using multimodal language. This study investigates speech disfluency and gesture production of 5- and 7-year-old Turkish monolingual (N = 61) and Turkish–English bilingual children (N = 51). We examined monolinguals’ Turkish narratives and bilinguals’ Turkish and English narratives. Results indicated that bilinguals were more disfluent than monolinguals, particularly for silent and filled (e.g., umm) pauses. Bilinguals used silent pauses and repetitions (e.g., cat cat) more frequently in English than in Turkish. Gesture use was comparable across language and age groups, except for iconic gestures. Monolinguals produced more iconic gestures than bilinguals. Children's overall gesture frequency predicted disfluency rates only in Turkish. Different gesture types might be orchestrated in the multimodal system, contributing to narrative fluency. The use of disfluency and gesture types might provide insight into bilingual and monolingual children's language development and communication strategies.

Listeners are sensitive to speech sounds’ probability distributions. Distributional training (DT) studies with adults typically involve conscious activation of phoneme labels. We show that distributional exposure can shift existing phoneme boundaries (Spanish /e/–/i/) pre-attentively. Using a DT paradigm involving two bimodal distributions we assessed listener's neural discrimination across three sounds, showing pre-to-post-test improvement for the two adjacent sounds that fell into different clusters of the trained distribution than for those that fell into one cluster. Upon unattended exposure to an intricate stimulus set, listeners thus relocate native phoneme boundaries. We assessed whether the paradigm also works for category creation (Spanish establishing a duration contrast), where it has methodological advantages over the usual unimodal-versus-bimodal paradigm. DT yielded a greater effect for the /e/–/i/ boundary shift than for duration contrast creation. It seems that second-language phoneme contrasts similar to native ones might be easier to acquire than new contrasts.