Navigating Language in Dementia Care: Bilingualism, Communication, and the Untapped Potential of Speech-Language Pathologists

Abstract

Aim: As the global population ages, the number of bilingual individuals living with dementia is increasing, yet their communication needs remain underrepresented in both clinical practice and research. This evidence review examines the intersection of language regression, communication challenges, and cultural–linguistic identity in bilingual dementia, with a particular focus on the role of speech–language pathologists (SLPs). Methods: Twelve peer-reviewed studies were critically reviewed and thematically analysed across four domains: (1) language regression and retention in bilingual dementia, (2) communication challenges in bilingual dementia care, (3) the marginal role of speech–language pathology, and (4) cultural–linguistic identity and health equity. The included studies span clinical case reports, experimental research, qualitative caregiver studies, and systematic reviews, with bilingual populations across Asia, Europe, North America, and the Middle East. Results: Findings reveal that language deterioration in bilingual dementia is dynamic and highly individualised, often influenced by language history, emotional context, and usage patterns. Caregivers and clinicians face persistent communication breakdowns, particularly in linguistically mismatched settings. Despite their specialised expertise in communication, SLPs remain largely peripheral in dementia care, constrained by systemic, educational, and methodological barriers. Moreover, linguistic and cultural identity play a critical role in how dementia is experienced and managed, yet are rarely integrated into care frameworks. Conclusions: This review highlights a significant knowledge–practice gap in bilingual dementia care and underscores the need to embed culturally and linguistically responsive communication practices, especially through speech–language therapy, at the centre of bilingual dementia care and support. It outlines key research and practice directions to advance equity, accuracy, and relational care in this growing population.

1. Introduction

Dementia, particularly Alzheimer’s disease (AD), is a global public health priority affecting over 55 million people worldwide and placing increasing demands on healthcare systems, caregivers, and society at large [1]. In addition to memory and executive functioning deficits, dementia is marked by progressive deterioration in communication, manifesting as word-finding difficulties, reduced verbal fluency, impaired comprehension, and diminished ability to participate in conversation [2]. These impairments are not peripheral but central to the lived experience of dementia and its impact on relationships, autonomy, and identity.

As global populations age and become more linguistically diverse due to increased migration, there is growing recognition that bilingual individuals may experience distinctive dimensions of dementia that intersect with their language histories. Bilingualism can influence cognitive processes, how language loss unfolds, how communication challenges emerge in care settings, and how personal and linguistic identity is maintained or disrupted. Studies suggest that bilingual individuals with dementia often experience distinctive patterns of language regression, involuntary code-switching, or reversion to a dominant or first-acquired language, patterns shaped by emotion, context, and social interaction [3,4]. These complexities create unique communicative challenges that extend to families and care providers, particularly when language mismatches exist between the person with dementia and their caregivers [5,6].

Effective communication is not simply a means of managing symptoms; it is a foundation for dignity, connection, and personhood in dementia care [7,8]. In bilingual contexts, this becomes even more important and more difficult. Yet despite this, speech–language pathology services remain underutilised, under-researched, and inconsistently integrated into dementia care for bilingual populations [9]. Speech–language pathologists (SLPs) are well-positioned to address communication breakdowns, support caregiver strategies, and foster inclusive communication environments, but current bilingual dementia care systems seldom prioritise this role. While the review acknowledges the full continuum of dementia progression, its focus is primarily on the early to moderate stages, where communication remains central to daily functioning and SLP services are most impactful. Importantly, this review does not suggest that bilingual individuals have a greater claim to SLP services than monolingual individuals; rather, it highlights the unique communicative trajectories and unmet clinical needs that arise specifically in bilingual dementia, which are rarely accounted for in mainstream service models or standardised tools.

While bilingualism has been associated with cognitive advantages, including delayed dementia onset through enhanced executive control [10,11], the communicative challenges it introduces in later life are significantly less explored. Much of the existing literature focuses on cognitive outcomes or monolingual language decline, offering little insight into real-world communication, relational dynamics, or the clinical implications for speech–language intervention. Although many of the communication difficulties observed in dementia are shared by monolingual and bilingual individuals, the bilingual experience introduces additional challenges, such as language switching, regression to a first language, and the emotional and practical effects of language mismatch between patient and caregiver, etc., that require tailored assessment and intervention strategies.

There remains a clear gap in the literature: few studies address how bilingual individuals with dementia experience language loss in everyday contexts, how caregivers navigate linguistic fragmentation, or how health professionals, including SLPs, can meaningfully support bilingual communication. Research in this area is also limited by a lack of culturally and linguistically appropriate assessment tools, clinical protocols, and intervention models tailored to bilingual dementia populations [5]. SLPs are uniquely positioned among healthcare professionals to address both the structural and pragmatic aspects of language loss in dementia. Unlike psychologists or social workers who may focus on emotional well-being or system navigation, SLPs provide targeted support in communication rehabilitation, multilingual assessment protocols, and training for caregivers to maintain meaningful interaction. This expertise is especially critical in cases where code-switching, regression to a heritage language, or language-mismatch with caregivers disrupt daily communication.

In response, this review synthesises current evidence across the twelve most relevant key studies in the past fifteen years, when bilingual dementia care gained increased attention, that examine the intersections of bilingualism, dementia, and speech–language pathology. Drawing from qualitative, quantitative, and mixed-method research, it identifies recurring patterns and critical insights across four central themes, including language regression and retention, communication challenges in bilingual dementia care, the marginal role of speech–language pathology, and cultural–linguistic identity and health equity. The aims of this review are to

• Identify core patterns in bilingual dementia communication and caregiving;
• Evaluate the current scope and integration of SLP services in bilingual dementia contexts;
• Highlight key gaps in research, policy, and practice;
• Provide recommendations to inform future research and the development of equitable, communication-focused care models.

By bringing together disparate strands of literature, this review seeks to foster a greater understanding of the communicative realities of bilingual individuals living with dementia and to advocate for inclusive, linguistically responsive approaches that uphold personhood and connection across the trajectory of care.

2. Methods

This evidence review adopts a structured, theory-informed approach to synthesising current literature at the intersection of bilingualism, dementia, and speech–language pathology. Although it does not conform to the rigid parameters of a systematic or scoping review, this methodology was intentionally selected to allow for analytical flexibility across a small but heterogeneous body of research. The approach prioritises conceptual depth, interdisciplinary relevance, and clinical applicability while adhering to high standards of transparency and thematic rigour. Given the conceptual and interdisciplinary nature of this emerging field, the review draws on a structured but flexible methodology to identify core insights, thematic patterns, and areas for future inquiry.

A comprehensive literature search was conducted across major databases, including PubMed, PsycINFO, CINAHL, and Google Scholar. Search terms were iteratively refined to capture core constructs, including bilingualism, dementia, Alzheimer’s disease, language loss, communication, speech–language pathology, and dementia care. The search was limited to peer-reviewed studies published in English between 2010 and 2024 to ensure currency while capturing foundational insights in this evolving field.

Inclusion criteria focused on empirical or review-based studies involving bilingual individuals with dementia that addressed communication-related issues or explored the role of speech–language pathologists. Studies were excluded if they examined monolingual populations only, addressed bilingualism solely as a protective factor without reference to communication, or focused exclusively on cognitive or pharmacological outcomes. A wide range of study designs was eligible, including qualitative research, case studies, mixed-methods inquiries, and cross-sectional surveys. Final inclusion was determined through a qualitative appraisal of each article’s methodological transparency, conceptual clarity, and relevance to the intersection of bilingualism, dementia, and communication support. Studies that lacked sufficient detail to support interpretive synthesis, or that addressed dementia in bilingual populations without a clear focus on communication or speech–language pathology, were excluded. This approach allowed for the inclusion of diverse methodologies while ensuring analytical depth and clinical relevance.

Twelve studies were ultimately selected following a two-stage screening process involving abstract review and full-text analysis. Each article was assessed for thematic relevance, conceptual clarity, and methodological quality. The final selection represents a diverse, interdisciplinary sample spanning healthcare, linguistics, gerontology, and speech–language therapy. Importantly, while not a systematic review or meta-synthesis, this targeted evidence review offers a rigorous and transparent synthesis of relevant literature. The limited number of included studies and the predominance of narrative designs constrain generalisability and empirical comparison. However, the purpose of this review is not to exhaustively quantify findings but to surface critical themes and conceptual gaps that warrant further empirical attention.

Data from the selected studies were analysed using Braun and Clarke’s reflexive approach to thematic analysis [12,13,14]. Each article was read multiple times to support deep familiarisation. Coding drew on both inductive and deductive strategies, with a focus on recurring patterns related to language regression, communication breakdowns, carer experiences, and the marginalisation of speech–language pathology. Themes were developed through iterative coding, constant comparison, and validation against the broader research context. This method was intentionally chosen to capture the socio-linguistic complexity of bilingual dementia, which would likely be overlooked using stricter methodological paradigms. The reflexive thematic synthesis allowed for the integration of clinical, psychosocial, and cultural insights across disciplines and study designs, therefore, enabling a richer understanding of the communicative dimensions of bilingual dementia.

Several limitations are acknowledged. Restricting the review to English-language publications may have excluded relevant work from non-Anglophone contexts. For example, the geographic concentration of included studies in Western contexts reflects the available peer-reviewed English-language research on this topic. This review does not capture unpublished or locally disseminated work from linguistically complex non-Western regions, which may offer crucial perspectives on bilingual dementia care. Future evidence syntheses should include multilingual databases and grey literature to address this gap. In addition, the interpretive nature of thematic analysis introduces subjectivity, though this was mitigated through methodological reflexivity and triangulation of themes across the selected studies, which was achieved through constant comparison across the twelve selected studies, representing diverse methodologies, populations, and perspectives. Each theme emerged from multiple sources, ensuring that patterns were not isolated findings but reflected recurring or convergent issues across the evidence base. Themes were revisited and refined in light of new data during multiple stages of coding, which supports both internal coherence and external validity.

Overall, this review aims to offer a robust and conceptually grounded synthesis of a field where traditional systematic methods may fall short. It provides a flexible yet rigorous model for interrogating how communication is experienced, understood, and supported, or neglected, in bilingual dementia care.

3. Results

The twelve studies included in this review span a diverse range of geographic, cultural, and clinical contexts, reflecting the complexity of bilingualism in dementia care. These studies were categorised into four interrelated themes that capture the multidimensional nature of communication in bilingual dementia: (1) language regression and retention in bilingual dementia, which explores patterns of bilingual language deterioration; (2) communication challenges in bilingual dementia care, focusing on interactional barriers between clients and caregivers; (3) the marginal role of speech–language pathology, examining the limited involvement of SLPs despite their clinical relevance; and (4) cultural–linguistic identity and health equity, which highlights how language and culture shape access to and experience of care.

Table 1. Summary of included studies categorised by theme.

Themes	Studies	Study Contexts	Study Design	Population	Language Pairs	Main Findings	Implications	Gaps
Communication Challenges in Bilingual Dementia Care	Brice et al. (2014) [3]	Caregivers and clinicians in the UK	Case Study	Single bilingual/bicultural individual with Alzheimer’s dementia over one year.	Not explicitly stated	Communication breakdown was a dominant concern. Lack of shared language led to misinterpretations and distress.	Need for inclusive communication training for all caregivers.	Few empirical trials on communication strategies in multilingual settings.
	Veenstra et al. (2014) [15]	Care in long-term facilities	Observational and interview data analysis	26 Frisian-Dutch bilingual individuals with mild to moderate dementia. The participants had a probable diagnosis of Alzheimer’s disease, confirmed by NINCDS-ADRDA criteria. Their median age was 86 years, with a range of 61–96 years.	Frisian-Dutch	Multilingual clients used gestures and code-switching as compensatory strategies; staff often lacked training.	Support systems must include multilingual communication scaffolds.	Limited observational data on interaction patterns over time.
	Shatnawi et al. (2023) [16]	Jordanian dementia context	Integrative Review	People with dementia from culturally and linguistically diverse backgrounds and their family caregivers.	Not explicitly mentioned, as the review broadly addresses cultural and linguistic diversity in dementia-friendly communities.	Caregivers reported frustration due to clients switching languages or becoming non-verbal.	Greater support for multilingual caregiving is urgently needed.	No local guidelines for multilingual dementia management.
Language Regression and Retention in Bilingual Dementia	Stilwell et al. (2016) [2]	Review of bilingual AD cases across clinical and experimental literature	Narrative review	The reviewed studies primarily included bilingual participants diagnosed with probable Alzheimer’s disease. Some studies also included control groups.	The studies reviewed covered various language combinations, including: Spanish-English, Swedish–Finnish, Swedish–Spanish, German–English, Russian–English, and French–English.	Language regression in AD often follows a ‘first-in, last-out’ pattern, though inconsistently. Both L1 and L2 deterioration depend on language use, dominance, and emotional context.	Assessment must account for shifting language dominance and bilingual profiles.	Lack of longitudinal studies tracking bilingual language decline; limited bilingual-specific tools.
	Nanchen et al. (2017) [4]	Swiss memory clinic data meta-analysis	Retrospective chart review of bilingual clients	Elderly bilingual and multilingual individuals with cognitive decline and dementia	Not explicitly mentioned.	Language reversion and lexical errors observed in bilinguals with dementia; complex patterns depend on language history.	Clinicians must document language background carefully to interpret symptoms accurately.	Standardised procedures for bilingual language documentation are lacking.
	Grasso et al. (2024) [5]	Case series of bilingual clients in Italy	Clinical case analysis	Bilingual individuals with PPA and the speech–language pathologists serving them.	Not explicitly mentioned.	Bilingual clients presented with variable patterns of regression across L1/L2; assessment was challenging without appropriate tools.	Calls for detailed linguistic profiling and flexible assessment.	No validated bilingual diagnostic pathway; limited generalisability of case data.
The Marginal Role of Speech–Language Pathology	Dimitriou et al. (2024) [17]	Systematic review and meta-analysis of randomised controlled trials (RCTs) on cognitive-linguistic interventions	Systematic review	People with Alzheimer’s disease	Not explicitly mentioned.	Language-cognitive interventions showed moderate gains; the role of language therapy is under-researched.	Multilingual SLP intervention development should be prioritised.	Scarcity of high-quality RCTs on bilingual communication therapy.
	Chen & Yow (2023) [10]	Singapore, bilingual adults	Cross-sectional executive function study	48 cognitively healthy older adults and 43 cognitively impaired older adults	Not explicitly mentioned.	Cognitive reserve effects varied with the bilingualism index; SLP implications are indirect.	SLPs must assess beyond self-reported proficiency.	No SLP-specific application; lacking ecological validity.
	Han et al. (2021) [9]	Korean-American community	Intervention pilot with bilingual Community Health Workers (CHWs)	Korean American elders with dementia and their caregivers.	Korean-English	Improved literacy and health access, but SLP was not integrated.	SLP integration into community dementia outreach is possible and necessary.	Role of SLP in CHW models underexplored.
Cultural–Linguistic Identity and Health Equity Considerations	Motta-Ochoa et al. (2021) [6]	Quebec, Canada–immigrant families	Qualitative ethnographic study	A culturally diverse group of persons with dementia, their caregivers, and staff members (from a non-profit organisation in Canada)	English-French	Language, memory, and identity are deeply intertwined; reverting to L1 was emotionally meaningful.	Care should preserve communicative identity as a human right.	Absence of language-sensitive ethics frameworks.
	Mendez et al. (2019) [18]	Latinx patients in the USA	Neuropsychological testing of bilingual clients	253 patients with probable Alzheimer’s disease (from a clinic serving a large immigrant population).	X (L1)-English (L2)	L2 dominance can mask L1 decline; culturally validated norms are missing.	Test selection and interpretation must consider the cultural–linguistic profile.	The majority of norms are based on white, English-speaking cohorts.
	Fisher & Schweizer (2014) [19]	CALD families in Australia	Thematic analysis of family and clinician interviews	bilingual individuals and those with or at risk of dementia.	Not explicitly mentioned	Cultural mismatch hindered diagnosis and care-seeking; bilingualism was often misinterpreted.	Need for cultural training among healthcare providers.	Little to no SLP representation in cultural competence programmes.

provides a summary of the key studies under each theme.

Together, these themes illustrate a striking disparity between the central role of communication in dementia and the peripheral attention it receives in practice, particularly for bilingual individuals. The findings expose not only clinical and systemic blind spots but also opportunities for speech–language pathology to contribute meaningfully to a more inclusive and person-centred model of dementia care.

3.1. Language Regression and Retention in Bilingual Dementia

Language regression, especially reversion to a first or emotionally dominant language, was a recurring theme across studies examining bilingual individuals with dementia. Stilwell et al. [2], in their narrative review, found that regression to the first-acquired language (L1) is common but not universal. Factors such as frequency of language use, recency of acquisition, emotional salience, and sociolinguistic context modulated which language was retained or lost. Similarly, Nanchen et al. [4], drawing on clinical data from a Swiss memory clinic, documented variable patterns of language reversion, underscoring the importance of detailed language histories in diagnosis.

Clinical case reports by Grasso et al. [5] reinforced these observations and demonstrated that standardised assessment procedures failed to account for the dynamic linguistic profiles of bilingual individuals, leading to misdiagnoses or overlooked symptoms. The reported cases showed that language regression did not follow a uniform trajectory but was mediated by the person’s linguistic background and environmental exposure.

Taken together, these studies challenge the assumption of a linear or predictable language decline and instead emphasise the need for individualised, bilingual-sensitive assessments. They also highlight the inadequacy of monolingual cognitive screening tools when applied to bilingual populations, as these tools often misattribute language-related retrieval issues to broader cognitive impairment.

3.2. Communication Challenges in Bilingual Dementia Care

Studies focusing on caregiver and care-provider experiences consistently reported communication difficulties when interacting with bilingual individuals with dementia. Brice et al. [3], using focus groups in the UK, found that language mismatch between clients and professional caregivers was a source of distress and disengagement. Caregivers struggled with interpreting meaning when clients code-switched or reverted to a less familiar language, often leading to breakdowns in care.

In residential care settings, Veenstra et al. [15] observed that residents frequently employed non-verbal strategies, gestures, and language mixing to communicate. Yet, these efforts were often misunderstood or ignored by staff lacking multilingual training. Shatnawi et al. [16] also reported that caregivers found it challenging to respond when clients switched between dialects or languages, or when verbal output ceased altogether.

Across these studies, a consistent theme emerged: while communication is central to care quality and relational well-being, few systems are equipped to support multilingual interaction. The challenges faced were not solely linguistic but also institutional, arising from insufficient training, limited interpreter access, and systemic undervaluing of communication as a clinical priority.

These findings suggest that effective dementia care for bilingual clients requires more than translation; it demands a holistic understanding of how multilingual individuals express needs, memories, and emotions, especially as language abilities fluctuate.

3.3. The Marginal Role of Speech–Language Pathology

Despite the centrality of communication in the dementia experience, the reviewed studies indicate that SLPs remain significantly underutilised in bilingual dementia care. Dimitriou et al. [17] found that while combined language-cognitive therapies show promise in improving naming, fluency, and quality of life, few interventions explicitly targeted bilingual populations, and none were designed or led by SLPs. This gap highlights the limited presence of communication specialists in intervention development for multilingual clients with dementia.

Han et al. [9], in a community-based intervention with Korean-American older adults, demonstrated that bilingual community health workers (CHWs) can effectively raise dementia literacy and facilitate diagnosis. However, SLPs were absent from the intervention model, despite the heavy emphasis on communication difficulties. The study offers indirect support for embedding SLP expertise in culturally grounded, community-led dementia programmes.

Chen and Yow [10], while not focused on SLPs directly, offered experimental evidence that bilingualism may confer differential cognitive control effects in healthy versus cognitively impaired adults. The study raises implications for how SLPs conceptualise executive function and language use in bilingual clients, yet the lack of translation into clinical tools or practice models remains a significant limitation.

Together, these studies show that although speech–language pathology has much to offer bilingual dementia care, particularly in assessment, intervention design, and caregiver training, its role remains marginalised. Structural barriers, lack of bilingual-specific tools, and insufficient integration into broader dementia frameworks all contribute to this underrepresentation.

3.4. Cultural–Linguistic Identity and Health Equity Considerations

The final theme synthesises studies that highlight the intersection of language, identity, culture, and equity in the dementia experience. Motta-Ochoa et al. [6], through an ethnographic study of immigrant families in Quebec, revealed how reverting to one’s first language in dementia was experienced not merely as linguistic regression, but as a reactivation of emotional memory and cultural belonging. The authors argue that maintaining access to this “language of the self” is vital to dignity and quality of life in late-stage dementia.

Similarly, Mendez et al. [18] demonstrated through neuropsychological testing of Latinx clients in the U.S. that second language (L2) dominance may obscure early L1 deficits, leading to misdiagnosis. The study called for culturally validated assessment norms that reflect bilingual cognitive trajectories rather than relying on monolingual benchmarks. Fisher and Schweizer [19] added to this picture from an Australian context, reporting that cultural misunderstandings between providers and clients from culturally and linguistically diverse (CALD) backgrounds often delay diagnosis and reduce engagement with services.

These studies collectively underscore the ethical and practical importance of recognising communicative diversity as a core component of equitable dementia care. They also point to a broader absence of linguistically inclusive policies, assessment norms, and care models that account for the sociocultural context of language use. Without deliberate efforts to embed cultural–linguistic identity into dementia care planning, bilingual individuals remain at heightened risk of underdiagnosis, miscommunication, and social isolation.

The reviewed evidence calls for a more inclusive understanding of dementia communication–one that recognises culture and language as interdependent. Speech–language pathology, as a discipline grounded in communication, is well-positioned to take the lead in developing culturally responsive models that bridge linguistic, cognitive, and social domains.

4. Discussion

4.1. Language and Communication Challenges

The evidence review affirms that while all individuals with dementia face cognitive-linguistic decline and related communication challenges, bilingual individuals may also contend with a distinctive set of difficulties shaped by language dominance, emotional salience, and shifting contextual use across languages. The studies reviewed [2,4,5] confirm that language deterioration does not follow a predictable linear path. While regression to L1 is often reported, individual trajectories vary widely depending on sociolinguistic factors such as age of acquisition, immersion, and emotional resonance.

What emerges is a distinct communicative profile in bilingual dementia–not simply “twice the decline,” but an interplay of loss, reversion, and strategic adaptation. These findings highlight that language shift is often contextually driven and socially mediated, complicating both assessment and care planning. Although identity-related communication challenges also affect monolingual individuals with dementia, the bilingual context often amplifies these challenges by introducing language discontinuities that disrupt established communication patterns and emotional resonance. Standardised tools and care frameworks grounded in monolingual assumptions, therefore, are ill-suited to this variability and risk misinterpreting language regression as general cognitive decline, as noted in cases by Grasso et al. [5] and Mendez et al. [18].

In parallel, other studies [3,15,16] illustrate how care environments often amplify these difficulties. Misalignment in language between clients and caregivers leads to communication breakdowns, emotional frustration, and relational strain. These interactional issues are not merely linguistic but relational and systemic, exacerbated by limited access to interpreters, lack of multilingual staff training, and poorly adapted communication strategies. The reviewed studies collectively point to the need for proactive, bilingual-sensitive communication planning as central to dementia care, rather than as an ancillary consideration.

4.2. SLP Involvement in Bilingual Dementia Care

Across the reviewed evidence, speech–language pathology is repeatedly identified as underutilised in dementia care, particularly for bilingual populations. Studies that explicitly consider the role of SLPs [9,17] reveal a concerning absence of these professionals in intervention planning, assessment, and family support. Despite the communication-focused nature of dementia symptoms, SLPs are infrequently involved in designing or delivering care for bilingual individuals.

This marginalisation is not reflective of disciplinary relevance but rather of systemic gaps in service integration and clinical training. Han et al. [9], for example, described a promising CHW-led model for dementia literacy among Korean American families, yet speech–language pathologists were not incorporated into the intervention team, despite evident communication-related outcomes. Similarly, Dimitriou et al. [17] found that most language-based dementia interventions lacked linguistic adaptation for bilingual individuals, and few were grounded in functional communication goals typically championed by SLPs.

Barriers to involvement appear multifactorial. As Chen and Yow [10] noted, cognitive-linguistic effects of bilingualism are highly variable and often require nuanced interpretation, skills that many general practitioners or dementia specialists may not possess. Without embedded speech–language pathology services, this complexity remains unaddressed, and clients are underserved. Compounding this issue is the global shortage of multilingual clinicians and the limited availability of validated assessment tools that are sensitive to bilingual language trajectories [5,18].

Collectively, the reviewed studies point to a disconnect between the centrality of communication in bilingual dementia and the peripheral role SLPs are currently afforded in care systems. Rectifying this gap is not just a clinical opportunity but an ethical imperative in CALD populations.

4.3. Structural and Conceptual Barriers to SLP Underutilisation in Bilingual Dementia Care

The limited integration of speech–language pathology into bilingual dementia care, as revealed by this review, stems from a combination of structural, educational, and conceptual barriers. Structurally, most health systems continue to treat SLPs as auxiliary rather than core members of dementia care teams. Referrals, where they occur, are often reactive and triggered by severe behavioural or swallowing issues, rather than proactive responses to emerging communication difficulties. For example, Grasso et al. [5] demonstrated how communication difficulties in bilingual clients were documented, but not met with corresponding referrals or intervention, largely due to the absence of bilingual-specific protocols or expectations of improvement.

At the educational level, gaps in pre-service training leave many SLPs unprepared to work with neurodegenerative conditions, especially in CALD populations. Few programmes offer specialised training in bilingual language assessment for adults, and even fewer integrate dementia communication within bilingual frameworks. This underpreparation may explain why, as Han et al. [9] reported, SLPs were almost entirely absent from a culturally sensitive, communication-focused dementia literacy initiative.

While the biomedical model rightly emphasises dementia’s neurodegenerative basis, clinical practice may underemphasise how communication can still be supported, adapted, and meaningfully preserved, especially in bilingual contexts. Speech–language pathologists do not simply communicate with clients; they provide therapeutic interventions to support communication and swallowing, both of which may be impacted by language regression, code-switching, and cultural–linguistic mismatches. These challenges are often more pronounced for bilingual individuals, who may lose access to their dominant language in care settings, face diagnostic mischaracterisation due to inappropriate tools, or experience relational breakdowns with caregivers who do not share their language. A more inclusive model of care, therefore, complements biomedical understanding with relational and identity-preserving strategies that centre communication as a core component of quality dementia care. Dimitriou et al. [17] highlighted that intervention studies tend to prioritise memory or naming accuracy, with less attention given to interactional or emotional outcomes that align with person-centred care models.

Finally, the lack of culturally valid assessment tools and intervention frameworks remains a persistent barrier. As Mendez et al. [18] and Nanchen et al. [4] emphasised, applying monolingual norms to bilingual speakers with dementia introduces risks of misdiagnosis, inappropriate goal setting, and missed opportunities for communication support.

Figure 1 outlines a common care pathway for bilingual individuals with dementia, highlighting where opportunities for early identification and intervention by speech–language pathologists (SLPs) are often missed. While some steps may also apply to monolingual dementia care, the figure underscores bilingual-specific barriers such as the misattribution of symptoms to typical bilingual ageing, the use of monolingual assessment tools, and culturally and linguistically mismatched communication support.

4.4. Diverging Hypotheses and Conceptual Tensions in the Literature

Although the reviewed studies broadly agree on the challenges bilingual individuals face in dementia, several conceptual tensions remain, particularly regarding language regression, the protective effects of bilingualism, and the interpretation of code-switching.

A central point of divergence is the “first-in, last-out” hypothesis of language regression. While Nanchen et al. [4] observed a consistent shift back to the L1 in bilingual clients with dementia, Stilwell et al. [2] and Grasso et al. [5] presented more variable patterns, including parallel decline and L2 retention in cases where the second language had been dominant for decades. These findings reinforce the idea that regression in bilingual dementia reflects not only underlying neural decline but also the dynamic interaction of language use, affective context, and social exposure: factors that modulate how neurobiological changes manifest in communication. No single regression trajectory can fully account for the layered and language-specific challenges encountered by bilingual individuals with dementia, whose communication is influenced not only by neural decline but also by shifting language dominance, code-switching patterns, and sociolinguistic context.

There is also a lack of consensus regarding the cognitive reserve hypothesis. Although this review did not directly focus on neuroprotective effects, studies such as Chen and Yow [10] indirectly interrogate bilingualism’s contribution to executive function. Their findings suggest that bilingualism’s effects are not universal and may depend on how bilingualism is defined (e.g., simultaneous vs. sequential, balanced vs. dominant), which complicates efforts to link language experience with delayed dementia onset.

A further conceptual debate surrounds the role of code-switching in bilingual dementia. While some clinical literature interprets code-switching as a sign of lexical failure or confusion, more socially informed studies [3,6] suggest it may be an adaptive strategy to maintain conversational flow or express affective nuance. These contrasting views have real-world implications: while one interpretation may lead to diagnostic concern and disengagement, the other frames language regression as a therapeutic opportunity to support communication through compensatory strategies, retained language use, and tailored caregiver training.

Rather than undermining the evidence base, these tensions point to the need for more nuanced, person-centred research that avoids overgeneralisation. The complexity of bilingual dementia defies universal models and instead calls for flexible frameworks that accommodate variation in language dominance, acquisition history, and communicative goals.

4.5. Practical Implications for Dementia Care and Speech–Language Pathology Practice

This review underscores the central role of communication in the lived experience of dementia, particularly for bilingual individuals whose language preferences, proficiencies, and identities shift in complex and often deeply personal ways. Across the studies reviewed, communication breakdown was not simply a clinical symptom but a relational rupture that profoundly impacted caregiving, connection, and quality of life [3,6,16]. In these contexts, supporting communication becomes a form of care itself.

For dementia clinicians, this necessitates a re-evaluation of how language is understood and addressed. While the significance of linguistic identity and caregiver-patient communication continuity may appear self-evident, these factors are often neglected in practice, particularly in care environments shaped by monolingual assumptions or constrained by limited linguistic resources. Rather than viewing language loss as inevitable or secondary to cognitive decline, care teams must foreground communicative capacity as a dynamic and modifiable aspect of dementia support. For bilingual individuals, this includes recognising language preference, fluctuation in dominance, and the emotional role of the L1–particularly in late-stage dementia, where reversion to earlier languages often reflects a search for familiarity, identity, or comfort [4,18].

For speech–language pathologists, the implications are profound. The profession must position itself more centrally in dementia care for CALD populations, not merely as a provider of standardised assessment but as a collaborator in building flexible, culturally responsive, and relationship-focused communication strategies. Dimitriou et al. [17] and Han et al. [9] both point to opportunities for SLPs to lead in co-designing interventions that prioritise functional outcomes, such as maintaining conversation, engaging in storytelling, or preserving familial connection, over rigid linguistic correctness.

This also demands a shift in how SLPs are trained and deployed. Programmes must include specialised content on bilingual language decline, code-switching, and sociolinguistic dynamics of dementia, while services must foster partnerships between SLPs, caregivers, cultural brokers, and medical staff. It is important to note that as dementia advances into its late stages, the need for active language intervention may decrease, and the relevance of bilingualism as a clinical concern may wane. However, during the earlier phases, SLP input can be critical for maintaining meaningful interaction, supporting identity, and facilitating care planning.

At the system level, early SLP involvement in dementia pathways, particularly in CALD communities, could facilitate earlier identification of communicative changes, prevent caregiver distress, and support inclusion. This includes preparing caregivers with practical tools to navigate complex language shifts (e.g., reversion to a less shared or non-shared language), respond to culturally nuanced nonverbal cues, and affirm communicative identity in ways that respect bilingual individuals’ linguistic and cultural backgrounds as verbal expression declines [5,15]. As illustrated in Figure 2, communication breakdown in bilingual dementia arises from intersecting linguistic, cognitive, relational, and systemic factors. This model reflects how effective bilingual dementia care relies on culturally responsive communication strategies, with SLPs playing an essential role in supporting both linguistic needs and relational continuity.

Ultimately, embedding speech–language pathology into dementia care is not only clinically indicated but ethically essential. Doing so affirms communication as a human right, supports dignity across linguistic contexts, and aligns with person-centred, equity-focused approaches to ageing in multilingual societies.

5. Perspectives for Future Research

The findings of this review underscore that bilingual dementia should not be viewed as a linguistic variation in monolingual dementia but rather as a distinct clinical and communicative experience, shaped by complex interactions among language history, cultural identity, and systemic inequity. Yet, research and practice have struggled to keep pace with the complexity and urgency of these needs. To advance equitable, person-centred care, future research must move beyond descriptive studies and address foundational gaps in assessment, intervention, service delivery, and workforce training. This section outlines a forward-looking agenda grounded in the four core themes of the review. It identifies underrepresented areas in current scholarship, proposes targeted research questions, recommends methodological improvements, and calls for interdisciplinary and community-engaged approaches. Together, these directions aim to transform bilingualism from a barrier into a bridge, reframing it not as a clinical complication, but as a vital context for understanding, supporting, and connecting with individuals living with dementia.

5.1. Addressing Underrepresented Areas in Bilingual Dementia Research

The current evidence base remains disproportionately focused on monolingual populations, and the reviewed literature reveals major underrepresented areas requiring urgent attention. First, there is a consistent absence of culturally and linguistically appropriate assessment tools that reflect the lived experiences of bilingual individuals with dementia. Studies such as Nanchen et al. [4] and Mendez et al. [18] highlight how standardised tools, normed primarily on monolingual English speakers, fail to account for the variability in bilingual language use, such as code-switching, variable dominance, and shifting pragmatic strategies. Without adapted tools, assessment risks mischaracterising natural bilingual variation as cognitive impairment or underestimating retained language abilities.

Second, there is a notable lack of systematically developed intervention models for bilingual individuals with dementia. While Dimitriou et al. [17] reviewed language-cognitive therapies with some promise, few were explicitly designed for bilingual participants, and even fewer addressed the social-emotional or identity-related aspects of communication that were strongly evident in studies like Motta-Ochoa et al. [6] and Brice et al. [3]. These studies reinforce that interventions must go beyond lexical or naming accuracy and support relational, affective, and contextually appropriate communication across languages.

Third, there is limited representation of linguistically and culturally minoritised communities in existing research. Most included studies were based in North America and Western Europe. Yet populations facing compounded barriers, such as older migrants, non-English speakers in rural areas, or caregivers in under-resourced systems, face unique risks of misdiagnosis, service exclusion, and unmet needs [9,16]. These communities remain largely invisible in the current literature, and future research must prioritise their inclusion in both design and implementation.

5.2. Emerging Questions to Guide Future Inquiry

To address these gaps, future research must be guided by targeted and empirically grounded questions that reflect the real-world complexities of bilingual dementia care. One critical area involves adapting clinical frameworks to account for linguistic and cultural diversity. For instance, how can standard dementia care protocols incorporate detailed bilingual language histories and sociolinguistic profiles as a routine part of assessment? What culturally responsive indicators of communicative decline, such as changes in code-switching, gesture use, or conversational engagement, might improve diagnostic accuracy in bilingual populations?

Another priority involves evaluating new models of care that embed SLPs more proactively in dementia support. The underrepresentation of SLPs in CALD services raises key questions: What interdisciplinary models enable early, culturally responsive involvement of SLPs in bilingual dementia care? How can SLPs contribute to team-based assessments and interventions in memory clinics, primary care, or community health worker-led initiatives?

Additionally, communication support for caregivers deserves greater research attention, particularly when caregivers do not share the same language as the person with dementia. What strategies, tools, or technologies can help carers manage interaction when the person reverts to a non-shared L1? Studies like Veenstra et al. [15] and Shatnawi et al. [16] suggest that pragmatic scaffolding, gesture-based communication, and culturally anchored cues may be promising, but controlled trials and co-designed interventions are needed to validate and extend these insights.

By anchoring future research in these targeted questions, the field can move beyond describing disparities to designing sustainable, scalable, and contextually relevant solutions for multilingual ageing populations.

5.3. Advancing Methodological Rigour in Bilingual Dementia Research

Elevating the quality and relevance of research in bilingual dementia care will require addressing several persistent methodological limitations highlighted in the reviewed studies. Much of the current literature is based on case studies, retrospective chart reviews, or small-scale observational designs, which offer valuable insight but limit generalisability. To build a robust evidence base, future research must invest in longitudinal cohort studies, comparative bilingual–monolingual designs, and mixed-methods approaches that integrate both linguistic and psychosocial dimensions.

Longitudinal designs are particularly crucial to mapping the trajectories of language regression and retention across the dementia continuum. For instance, Nanchen et al. [4] and Stilwell et al. [2] suggest that patterns of language shift and reversion are highly individualised and may change over time. Tracking these shifts across disease progression and linking them to social, environmental, or emotional variables could help identify modifiable factors that support retained communicative function.

Equally important is the development and validation of assessment tools that capture the lived linguistic complexity of bilingual individuals. Current measures often focus narrowly on lexical or syntactic domains, while overlooking pragmatic features such as code-switching, gesture use, and emotional prosody–features that were repeatedly identified in this review [3,6]. Tools that incorporate ecologically valid outcomes, such as caregiver-reported communicative effectiveness or observed interaction success, would more accurately reflect the goals of real-world dementia care.

Language history documentation must also become a methodological standard. As Mendez et al. [18] and Chen and Yow [10] show, age of acquisition, context of language exposure, and current dominance all shape communicative performance and diagnostic interpretation. Without this information, clinicians and researchers risk misclassifying language-related symptoms or missing preserved communicative strengths.

Methodological advancement must therefore prioritise both scientific rigour and linguistic realism, ensuring that bilingual individuals are not only included in dementia research but accurately represented within it.

5.4. Drawing on Interdisciplinary and Community Perspectives

The multifaceted nature of bilingual dementia, spanning neurological, linguistic, cultural, and relational domains, necessitates a deeply interdisciplinary research approach. Collaborations with neuropsychologists, geriatricians, sociolinguists, anthropologists, and public health professionals can enrich both conceptual frameworks and methodological tools. For example, neuroimaging studies might illuminate the differential neural mechanisms underlying language retention in bilingual individuals, while ethnographic and narrative methods could capture how families interpret and respond to communicative change over time (as demonstrated by Motta-Ochoa et al. [6]).

Speech–language pathologists, in particular, can serve as a vital bridge between biomedical and psychosocial paradigms, linking cognitive findings with practical communication strategies and translating research into relationally meaningful interventions. However, their integration into interdisciplinary teams remains inconsistent and, as this review shows, often absent.

Equally critical is the inclusion of community voices in research planning and implementation. Participatory and co-designed methodologies can help ensure that research questions reflect lived experiences and that intervention strategies are acceptable, feasible, and contextually grounded. For example, Brice et al. [3] and Shatnawi et al. [16] highlight caregiver perspectives that are often overlooked in traditional research designs but are essential to designing usable support tools.

Community partnerships can also help surface knowledge from underrepresented groups, such as immigrant families, CALD older adults, and non-English-speaking caregivers, whose perspectives are largely missing from current literature. By drawing on community expertise, researchers can more effectively challenge monolingual and monocultural assumptions embedded in dementia care and co-create models that honour linguistic identity as central to care quality and personhood.

5.5. Translating Research into Practice and Policy

As the evidence base on bilingual dementia grows, the next critical challenge lies in ensuring that findings are translated into meaningful change across clinical practice, workforce training, and health policy. Despite strong qualitative and observational evidence that communication breakdown is central to the dementia experience in bilingual individuals [3,15,16], few findings have yet influenced formal care guidelines or service design. There remains a significant lag between what is known and what is done.

Translational research is essential to bridge this divide. For example, Dimitriou et al. [17] underscore the need for scalable communication interventions, yet these have not been trialled in routine service settings or adapted across diverse linguistic communities. Pilot studies could evaluate whether integrating SLPs into memory clinics, general practice, or culturally specific outreach programmes improves earlier identification of communication decline, reduces carer stress, or enhances care engagement.

One practical pathway for integrating SLPs more effectively involves embedding them within memory clinics or primary care teams, where they can participate in early screening, contribute to culturally and linguistically appropriate assessment, and support person-centred care planning. In community-based aged care settings, SLPs can deliver caregiver training tailored to specific language contexts and advise on strategies for supporting communication as dementia progresses. Pilot programmes in multicultural urban health systems have shown that involving SLPs at early stages helps reduce communicative isolation, improves diagnostic clarity, and enhances caregiver confidence in linguistically diverse households. These integrated models of care underscore the value of positioning SLPs not as auxiliary providers but as core contributors to interdisciplinary dementia support.

Technology also holds promise for translation. Telehealth platforms and app-based tools may offer scalable ways to deliver bilingual assessments, provide carer training in multiple languages, or support communication maintenance in home-based settings. However, as Grasso et al. [5] caution, such tools must be grounded in linguistic realities and co-designed with end users to ensure accessibility, cultural resonance, and effectiveness.

Policy also has a critical role to play. Aged care strategies and funding mechanisms must explicitly recognise communicative diversity as a component of quality care. This includes embedding requirements for language-sensitive assessment, incentivising workforce training in bilingual communication support, and supporting community-led models where SLPs collaborate with bilingual health workers, interpreters, and family carers.

Ultimately, effective translation will require aligning research agendas with practice priorities, building tools, models, and policies that are not only scientifically sound but also feasible, adaptable, and responsive to the real-world conditions of dementia care.

5.6. A Vision for the Future

Advancing research at the intersection of bilingualism, dementia, and communication is no longer a peripheral task–it is a necessary response to the demographic and ethical realities of ageing in multilingual societies. As this review has shown, bilingual individuals with dementia face distinctive risks of communicative breakdown, underdiagnosis, and relational disconnection, in part because their linguistic needs remain poorly understood and insufficiently supported in mainstream care.

The reviewed studies collectively call for a shift: from monolingual norms to multilingual responsiveness, from cognitive-centric models to communication-centred care, and from isolated disciplinary silos to collaborative, community-engaged research and practice. A future where speech–language pathologists are embedded in diverse dementia care teams, where assessment tools reflect lived language histories, where caregivers are equipped to support interaction in multiple languages, and where communication is treated not as an afterthought but as a human right, is not only possible but within reach.

There is also a critical need for studies originating from linguistically complex regions that remain underrepresented in the current evidence base. Research from non-Western, multilingual contexts is vital to understanding how bilingualism intersects with dementia care in settings characterised by diglossia, colonial language dynamics, and resource-constrained healthcare systems.

Achieving this vision will require sustained investment in research, interdisciplinary training, policy advocacy, and system redesign. But the payoff is substantial: care that is more inclusive, more person-centred, and more aligned with the identities, relationships, and voices of those it seeks to support.

In an ageing world shaped by increased migration, linguistic diversity, and increasing life expectancy, ensuring communicative dignity for bilingual individuals with dementia is both a scientific imperative and a moral one. The research directions proposed in this review offer a roadmap for getting there.

Table 2. Research gaps, questions, and recommended methodologies.

Theme	Key Research Gaps	Emerging Research Questions	Recommended Methodologies
Language Regression and Retention	Limited understanding of how bilingual individuals regress or retain languages across dementia stages; lack of longitudinal data capturing individualised trajectories.	How do patterns of language regression and retention evolve across stages of dementia in bilingual individuals?	Longitudinal mixed-methods studies with detailed language histories and repeated language profiling.
Communication Challenges in Care	Scarcity of research on multilingual interaction in caregiving settings; limited support tools for carers managing communication breakdown across languages.	What communication strategies are effective when caregivers and clients do not share the same dominant language in bilingual dementia care?	Ethnographic and participatory designs involving caregivers; pragmatic trials of multilingual communication aids.
Marginal Role of Speech–Language Pathology	Minimal integration of SLPs in bilingual dementia services; few intervention models or training programmes tailored for this population.	What interdisciplinary models of care effectively integrate SLPs into early dementia intervention for bilingual populations?	Implementation science frameworks to test new care models; comparative service delivery studies.
Cultural–Linguistic Identity and Health Equity	Underrepresentation of CALD and immigrant communities in research; lack of culturally grounded assessment tools and services reflecting linguistic identity.	How can assessment tools be adapted to reflect the cultural and linguistic realities of bilingual individuals with dementia?	Community-based participatory research; cross-cultural validation studies of assessment tools and screening protocols.

below summarises the key research gaps identified across the four themes of this review, alongside specific questions and methodological recommendations to guide future studies. This synthesis is intended to support researchers, clinicians, and policy makers in designing contextually relevant, communicatively equitable, and scientifically rigorous investigations into bilingual dementia care.

6. Conclusions

Bilingualism is no longer an exception in ageing populations, but rather a norm. Yet, the communicative needs of bilingual individuals with dementia remain profoundly overlooked in both research and care. This review synthesised twelve key studies that illuminate how language regression, interactional breakdowns, and cultural–linguistic identity shape the dementia experience in distinct and often misunderstood ways. Despite the centrality of communication, bilingual individuals are routinely assessed with monolingual tools, supported by care teams unprepared for linguistic diversity, and too often excluded from interventions designed to preserve interaction and relational well-being.

Crucially, the marginal role of speech–language pathologists is not a reflection of limited relevance, but of untapped potential. As experts in communication, SLPs are uniquely positioned to address the language-based and identity-related disruptions that characterise bilingual dementia. But realising this potential will require systemic change, from the development of bilingual-specific tools and intervention models to the integration of SLPs into culturally responsive, interdisciplinary dementia care frameworks.

Future research must be targeted, community-informed, and translational. It should be designed not only to fill academic gaps but to improve lives. This includes methodological innovation, investment in inclusive training, and collaboration across sectors to ensure that care reflects the lived linguistic realities of diverse ageing populations.

Ultimately, supporting communication in bilingual dementia is not simply a clinical task—it is a commitment to equity, personhood, and dignity. The voices of bilingual individuals with dementia deserve not only to be heard but to be understood, supported, and valued at every stage of care.