Language Co-Activation in Bilinguals

Decades of research have established that bilinguals do not switch off one language when using another. The resulting cross-language activation has been demonstrated across multiple levels of representation. However, the field lacks consensus on when such activation reliably occurs and when it does not, what factors modulate it, and how findings across levels of representation can be integrated into a coherent theoretical account. Proficiency, age of acquisition, language dominance, typological distance between languages, task demands, emotional state, and sociolinguistic context have all been implicated as modulating factors, yet their precise contributions and interactions remain far from fully characterized. Furthermore, the language representational levels themselves — sub-lexical, lexical, grammatical, syntactic, semantic, pragmatic — have often been studied in isolation, leaving open the question of whether cross-language activation takes a consistent form across levels or is governed by level-specific principles.

Recent methodological developments, including neuroimaging, computational modelling, pupillometry, brain stimulation, large-scale behavioral paradigms, and corpus-based approaches, offer new opportunities for considering converging evidence and integrated modelling. Simultaneously, the ever-growing prevalence of bilingualism opens new opportunities to examine cross-language activation in typologically diverse and understudied language contexts.

This Research Topic seeks to consolidate and critically advance understanding of cross-language activation across the full spectrum of linguistic representations in bilinguals. It invites contributions that interrogate the presence or absence of cross-language interaction, treating null or inhibitory effects as theoretically informative rather than as failures to replicate. The objective is to develop a more complete and constrained account of bilingual language architectures — one that specifies not only what is possible but also what is more or less probable under defined conditions.

We invite submissions for the following type of contributions:

• Empirical investigations of cross-language co-activation at sub-lexical, lexical, grammatical, syntactic, semantic, or pragmatic levels, with particular attention to constraints and modulating factors;
• Studies examining the absence, suppression, or inhibition of cross-language activation, the conditions under which they are observed, and theoretical implications;
• Integrative or comparative analyses across representational levels, addressing whether cross-language interaction operates according to unified or level-specific mechanisms;
• Theoretical and computational modelling contributions that account for both activation and lack thereof within a single framework;
• The role of individual differences — including proficiency, dominance, age of acquisition, typological distance, sociolinguistic context — in modulating cross-language interaction;
• Methodological contributions that advance the measurement and operationalization of cross-language activation at different levels of representation;
• Cross-linguistic investigations involving typologically diverse or understudied language pairings that test the generalizability of existing theoretical accounts;
• Implications of cross-language interaction findings for broader models of bilingual cognition, language control, and mental structure considered more broadly.

We welcome submissions of Original Research articles, Reviews, and Opinion papers. Contributions should engage explicitly with the theoretical implications of their findings for models of bilingual cognition and are encouraged to address both positive and null effects with equivalent rigor. It is strongly encouraged that submissions move beyond description of isolated phenomena toward principled accounts of the conditions governing cross-language interaction, thereby advancing a more predictive and falsifiable science of bilingual language processing.

Article types and fees

This Research Topic accepts the following article types, unless otherwise specified in the Research Topic description:

• Brief Research Report
• Case Report
• Clinical Trial
• Community Case Study
• Conceptual Analysis
• Curriculum, Instruction, and Pedagogy
• Data Report
• Editorial
• FAIR² Data
• ... View all formats

Articles that are accepted for publication by our external editors following rigorous peer review incur a publishing fee charged to Authors, institutions, or funders.

Article types

This Research Topic accepts the following article types, unless otherwise specified in the Research Topic description:

• Brief Research Report
• Case Report
• Clinical Trial
• Community Case Study
• Conceptual Analysis
• Curriculum, Instruction, and Pedagogy
• Data Report
• Editorial
• FAIR² Data
• General Commentary
• Hypothesis and Theory
• Methods
• Mini Review
• Opinion
• Original Research
• Perspective
• Policy and Practice Reviews
• Policy Brief
• Registered Report
• Review
• Study Protocol
• Systematic Review
• Technology and Code

Keywords: cross-language activation, bilingual language processing, language control and interaction, individual differences in bilingualism, computational and neurocognitive modelling

Important note: All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.