Perspective Chapter: How Can Psycholinguistic Researches Respond to Societal Needs

Abstract

This chapter examines prevailing trends in applied psycholinguistics centered on two pressing real-world imperatives—fostering equitable multilingual development and enabling clinical rehabilitation after language impairment. It first delineates how psycholinguistic approaches illuminate the intricate cognitive mechanisms underlying bilingual language representation, processing, and executive control during code-switching. Persistent challenges in validating assessments of multifaceted proficiency across languages are also discussed. Next, neural correlates of speech-language recovery are detailed, including insights from neuroimaging on how interventions harnessing both cognitive capacities and language networks can optimize outcomes. Additional coverage touches on augmenting naming accuracy in anomia through working memory training protocols. Ultimately, priorities in applied psycholinguistic research are rapidly transitioning from purely theoretical models toward substantively advancing educational accessibility and communication disorder interventions via illuminating authentic dynamics of language usage across diverse cultural settings. However, substantial lacunas remain in accounting for individual variability, motivational influences, and societal forces shaping both multilingual attainment and rehabilitation efficacy. Progress necessitates interdisciplinary collaboration integrating psycholinguistic and sociolinguistic perspectives to construct cohesive solutions that equitably benefit all global communities.

1. Introduction

Language, as a profound social phenomenon, propels collective human advancement while being shaped by the prevailing need to address significant issues in societal development [1]. Although sociolinguistic studies have extensively documented regional dialects, style-shifting, code-switching, language accommodation between speakers, and propagation of language change through communities, they lack detailed theories of the cognitive and psychological mechanisms driving these phenomena [2]. However, psycholinguistics can also provide theoretical insights into fundamental questions in sociolinguistics regarding how and why language varies across social contexts [3]. While richly describing empirical patterns in language variation, psycholinguistics can fill this gap through controlled experiments and computational models examining the perception, production, and processing of various languages [4, 5, 6].

In response to pressing real-world needs, contemporary research is increasingly directed toward fostering equitable multilingual development and addressing clinical rehabilitation challenges. Recent research initiatives are directing efforts toward advancing equitable multi-language education and improving communication accessibility for all. Cross-disciplinary approaches are actively addressing longstanding educational barriers through evidence-based policy revisions that promote multilingual inclusion. The advent of technology has facilitated the study of authentic discourse, with computational tools informing teaching strategies that strike a balance between fostering pride in native dialects and meeting the standards of prestigious language varieties. Scientists are dedicated to improving outcomes for individuals with speech-language impairments resulting from stroke or trauma. Neuroimaging techniques quantify residual language network integrity, guiding targeted interventions. Innovative apps are disseminating personalized exercises that maximize cognitive control gains, ensuring the preservation of tangible communication abilities and facilitating fuller participation in desired social roles. Understanding the psychological machinery that underlies expression within complex cultural contexts is increasingly valuable. Equitably fostering multilingual development and clinically rehabilitating speech-language impairments represent two branches of applied psycholinguistics research with profound human impacts in culturally diverse communities.

The remainder of this chapter specifically explores two critical real-world priorities: equitable multilingual development and clinical rehabilitation of speech-language impairments. Psycholinguistic perspectives on the intricate cognitive and neural processes underlying linguistic communication can inform substantial progress in overcoming barriers to accessibility and equity in language environments globally. The chapter summarizes and discusses findings from previous studies using experimental paradigms examining lexical access, syntactic processing, code-switching production, and assessment techniques across multiple languages. It also synthesizes research on neural mechanisms involved in post-stroke recovery and interventions boosting working memory to improve outcomes for language impairments like anomia. A key theme is tailoring treatment approaches based on the assessments of residual neurocognitive capacities on an individual basis. This literature review surveys cutting-edge applied psycholinguistic research while underscoring the need for interdisciplinary perspectives to equitably advance rehabilitation and multi-language development for diverse populations through addressing persisting gaps in the field.

2. Psycholinguistics studies in multilingual situational applications

The main purpose of the field of psycholinguistics is to uncover the universal cognitive mechanisms that govern language development, use, and breakdown [7]. However, psycholinguistics research has predominantly focused on Indo-European languages like English, making it difficult to determine if certain linguistic phenomena are English-specific or more universal. Exploring how code-switch occurs in multilingual environments and how to assess multilingual language can help determine when and how cross-language interactions shape outcomes [8]. However, before delving into these inquiries, it is essential to clarify how the research methods of psycholinguistics are practically applied in multilingual studies.

2.1 How psycholinguistic research methods apply in multilingual studies

The recognition that most of the world’s speakers are multilingual has sparked new areas of psycholinguistic research that examine how multilinguals manage to negotiate the presence of more than one language in the same mind and brain [9, 10, 11]. Further examination shows that psycholinguistics tries to explain multilingual processing through various models like the inhibitory control (IC) model [12], which proposes that bilinguals actively inhibit their dominant language (L1) to allow fluent production in the weaker language (L2). The control mechanisms that are in place to control more than two languages are much more variable and malleable than previously thought [13, 14]. Building on this understanding, we will now delve into the specific application of psycholinguistic research methods in the realm of multilingual lexical and syntactic processing.

2.1.1 Measuring lexical processing in multilingual studies

In measuring lexical processing in multilingual psycholinguistics, a common paradigm used to examine relative difficulty in accessing lexical items across languages is picture or word naming tasks. These tasks aim to explore lexical access by prompting participants to name pictures or words in L1, L2, or additional languages (Lx) [15]. The results consistently reveal the co-activation of representations of multiple languages, providing support for models wherein bilingual lexical representations are integrated across languages rather than kept separate [16]. Lagrou et al. [17] used a picture naming task where Dutch-English bilinguals named pictures in their L1 Dutch after reading distractor words. Distractor words slowed reaction times more when they were cognate translations or shared initial phonemes across languages, indicating cross-language activation spread to the non-target language. Other studies have examined how proficiency across languages impacts naming. Pictures with cognate names that overlap heavily across languages are named faster than non-cognates. Ibrahim [18] found that Arabic-English bilingual children showed bigger cognate facilitation effects in their weaker L2 English. They relied more on overlapping first-language representations to aid L2 production. These paradigms also provide insight into semantic and phonological processes underlying new L2 word learning. Comesaña et al. [19] taught adult English speakers new spoken L2 words paired with pictures. In a later naming test, newly learned words interfered more with picture naming for similar L1 words, suggesting lexical integration occurs through extending L1 semantic-phonological processes to incorporate new L2 items. Overall, the extensive utilization of multilingual naming paradigms has been instrumental in unraveling the intricacies of language co-activation and advancing our models of bilingual lexical retrieval. These studies have notably enriched our understanding of the effects of language proficiency, similarity, and interference in semantics and phonology between languages, shedding light on the mechanisms underpinning the acquisition of new L2 vocabulary. However, it is imperative to acknowledge the existing limitations in psycholinguistic research within this domain. One notable gap lies in the need for more nuanced investigations into the dynamic interplay between proficiency levels and lexical processing. Additionally, further examination is imperative around the dynamics of developing phonological and semantic representations in bilingual mental lexicons. Questions persist surrounding precisely how new L2 lexical items integrate into and potentially restructure existing first-language architecture over time. Investigations delineating emergent bidirectional cross-linguistic influences on the content and form of lexical representations promise more comprehensive models of the bilingual lexicon and complete L2 fluency cultivation programs.

2.1.2 Measuring syntactic processing in multilingual research

In measuring syntactic processing in multilingual processing, a core question is whether and how multilingual activate the syntactic representations of their different languages during production and comprehension. The research utilizes common psycholinguistics paradigms to tap into syntactic processing, including measuring event-related brain potentials (ERPs) during sentence reading and analyzing structural priming patterns in language production. ERPs allow tracking of how multilinguals incrementally analyze linguistic input. Studies measuring P600 effects, an ERP marker of syntactic processing difficulties, find effects emerge for grammatical violations in bilinguals’ weaker L2 at high but not lower proficiencies, suggesting co-activation emerges with greater experience [20]. Examining later anterior negativities instead, indexing deeper syntactic repairs, Hartsuiker et al. [21] found native-like ERP patterns were attained in bilinguals’ weaker language. This demonstrates their underlying syntactic representations can reach native-level processing capabilities through sustained language exposure. Research also uses structural priming paradigms where speakers tend to repeat recently encountered syntactic structures during production. Structural priming occurs both within a language and across languages in bilingual dialog, indicating abstract syntactic representations shared between languages can be co-activated to aid fluent processing [22]. Additionally, the strength of cross-language structural priming is asymmetric: Priming is greater from speakers’ dominant to weaker language. Cai et al. [23] proposed that the observed asymmetry in cross-language structural priming, with stronger priming from speakers’ dominant to weaker language, indicates a more significant influence from the firmly established syntax of the first language (L1) that guides the development of processes involved in producing the second language (L2). They clarify the developmental trajectories in attaining native-like processing capabilities across structurally related and distinct language pairings. In summary, these studies contribute significantly to our understanding of multilingual syntactic processing. They shed light on developmental trajectories toward achieving native-like processing capabilities across structurally related and distinct language pairings. Further studies might also consider the impact of cultural factors on syntactic co-activation.

2.2 Code-switching in multilingual environments

Code-switching, or alternating between multiple languages within a conversation, is a common linguistic behavior in many bilingual communities. Psycholinguistic research investigates the cognitive mechanisms enabling speakers to seamlessly integrate words and structures from distinct language systems. Computational models simulate the high-level processes modulating when and where switches occur. Bullock and Toribio [24] proposed an activation threshold mechanism where lexical items from the non-target language receive activation decay, allowing occasional highly activated lemmas to surpass the threshold and trigger code-switching. This accounts for item frequency and priming influences on switch points. Fricke and Kootstra [25] outlined selection processes where alignment to interlocutors and priming of language schemas jointly predict when speakers shift languages based on contextual factors.

Additionally, individual differences among bilinguals have been shown to modulate the processing costs incurred during comprehension of mixed-language input. Some studies have looked at how code-switching ability impacts processing load. Bilinguals who engage in less frequent code-switching in their daily language show increased activation in frontal cortical regions implicated in cognitive control when asked to comprehend code-switched speech [26]. This suggests those with better interference suppression and inhibition capacities may experience less processing difficulty when having to integrate inputs from alternating language schemas. The proficiency balance between a bilingual’s two languages has also been examined regarding switch costs. There is some evidence suggesting balanced bilinguals, with equivalent high proficiency in both languages, may process switches more efficiently than second-language dominant bilinguals [27]. Thus, while early and highly proficient dual language use predicts better code-switching production capability, and dominance in one language over the other may increase integration demands and disruptions when comprehending mixed-language speech. In summary, psycholinguistics research has identified cognitive and linguistic factors that enable fluent code-switching in bilingual communities. Computational models clarify influences on production switch points, such as lexical activation thresholds allowing unintended words to be uttered [24]. These studies delineate the multifaceted interactions between language control capacities and situational constraints that facilitate smoothly fusing elements of two rule-governed linguistic systems within a conversation.

2.3 Multilingual language assessment

Valid assessment of proficiency across multiple languages is critical for research and educational placement of multilingual learners. Psycholinguistics observations offer valuable insights into identifying the key components and employing effective techniques for assessing language proficiency.

Vocabulary knowledge is a robust indicator of overall ability and crucial for comprehension, assessed through Picture Vocabulary Tests. Gariot [28] explored the Peabody Picture Vocabulary Test (PPVT-4) as a tool for assessing vocabulary knowledge in English as a second-language (L2) learner. The study identified reliability concerns for those with limited L2 proficiency, particularly those scoring below 24 items. Additionally, linguistic characteristics, such as phonological similarity, influenced test outcomes. The study suggested caution in comparing PPVT scores across learners with different first languages, emphasizing potential confounding effects of first-language frequency and first-language-second-language similarity. Despite these limitations, the PPVT-4 remains a suitable measure for comparing more proficient L2 learners who share the same first language.

In employing Narrative Production Tasks, Sevilla et al. [29] delved into linguistic patterns associated with Formal Thought Disorder (TD). Analyzing narrative speech from 40 participants—20 with TD, 20 without, and 14 healthy controls—revealed significant differences in the misuse of noun phrases (NPs) for reference. Definite and pronominal NPs showed greater impact than indefinite and non-pronominal (lexical) NPs. These findings underscore TD’s specific linguistic profile, offering insights for neurocognitive understanding and potential clinical biomarkers.

Finally, sentence Judgment Tasks present isolated sentences and measure accuracy and reaction times in determining if they are grammatically correct or not [30, 31]. Performance, particularly speed, and N400 ERP components during processing become native-like only at high proficiencies, validating the fine-grained difficulty [32]. In summary, psycholinguistically informed measures, evaluating lexical, phonological, morphological, and syntactic competencies through controlled assessments, contribute significantly to understanding multilingual development. However, challenges such as potential biases and limitations exist. Future research should explore innovative methodologies, address existing gaps, and consider cultural and contextual factors that influence linguistic assessments in a multilingual context.

3. Psycholinguistic research in speech/language rehabilitation

3.1 Neural mechanisms supporting speech and language recovery

Investigating neural correlates of linguistic processes has become indispensable for developing highly effective intervention programs tailored to the neurocognitive needs of individuals with conditions such as stroke-induced chronic aphasia. A compelling illustration of this imperative is found in the work of Hartwigsen and Saur [33], where patients with stroke-induced chronic aphasia underwent intensive speech therapy while being simultaneously mapped with fMRI during language tasks. In a meticulously designed overt picture naming task, participants were required to verbally identify visually presented objects. This methodology allowed for the precise tracking of normalized activation in language regions such as the inferior frontal gyrus (IFG) and its correlation with naming improvements. The findings of this study shed light on the nuanced relationship between targeted therapeutic interventions, neural activity in language-specific regions, and subsequent enhancements in naming abilities. Similarly, Geranmayeh et al. [34] conducted a study involving aphasic stroke patients undergoing speech therapy utilizing a semantic feature analysis approach, all while undergoing fMRI scans during naming trials both pre- and post-treatment. The post-therapy observations revealed increased activation in key language regions, including the left IFG and superior temporal gyrus (STG), as well as in domain-general areas associated with cognitive control and attention during successful naming. This compelling evidence points to the simultaneous normalization of the language network and compensation from broader brain systems as crucial neural mechanisms underlying the observed improvements in speech production. This dual-process phenomenon showcases the intricate interplay between targeted language therapy, neural plasticity, and the engagement of broader cognitive resources, contributing significantly to our understanding of the neuro-functional systems involved in language control.

3.2 Boosting verbal working memory to enhance naming outcomes in anomia therapy

Psycholinguistic perspectives recognize language deficits after neurological damage stem from disruptions to the neurocognitive systems supporting domain-general capacities like working memory and cognitive control alongside language-specific networks. Intervention trials are thus increasingly assessing and reinforcing these resources in tandem to achieve maximal therapeutic gains.

Murray [35] supplemented traditional naming therapies with hierarchical working memory training for patients with anomia using reading span tasks. This approach aligns with psycholinguistic models that emphasize the retention of fine-grained lexical-semantic details through deep encoding strategies to minimize phonological decay during retrieval attempts. Patients were trained to elaborate word meanings and limn vivid mental images between items during span recall. Those receiving this augmented intervention exhibited naming accuracy improvements that persisted significantly longer at 6-month follow-up compared to standard naming therapy alone. This reveals the efficacy of targeting domain-general capacities his study quantitatively confirmed were compromised after stroke to support improved word production. Findings converge with wider cognitive neuropsychological frameworks situating language within interconnected networks managing attention and memory. Strengthening these systems through behavioral training and neural stimulation could optimize rehabilitation outcomes. Future priorities include profiling each patient’s residual neurocognitive capacities to guide ideal individualized treatment packages, co-training language and cognitive control.

4. Conclusions

In summary, contemporary psycholinguistics is actively investigating complex issues that profoundly impact linguistic communications in lives, ranging from promoting balanced proficiency in two dialects or languages to addressing challenges in clinical rehabilitation after language impairment. We have outlined existing evidence related to key priorities, including optimizing fluency in both directions (orally or in writing) between dialects or languages, facilitating maximal cognitive-linguistic gains after impairment, and supporting assessment mechanisms that allow for cross-linguistic comparisons. Looking ahead, statistical growth modeling could explicitly quantify how varying patterns of dual language exposure influences developmental trajectories in attaining equivalent and proficient fluency across both languages. Exploring individual variations will help identify the factors that most significantly predict learning trajectories across diverse populations. In addition, advances in neuroimaging techniques such as functional MRI (fMRI), electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRs) could provide insights into the neural mechanisms underlying bilingual language processing and acquisition [36], and more specifically, insights about the impact of inter-personal interactions and cultural/societal changes on the linguistic use. Computational modeling approaches could also help uncover the cognitive and neural processes involved [37]. These interdisciplinary methods incorporating neuroscience and computational science hold promise for gaining a more comprehensive understanding of psycholinguistic phenomena. These endeavors hold the promise of substantial progress, translating foundational psycholinguistic knowledge into genuinely equitable and accessible linguistic environments, enabling all global citizens to communicate effectively in our increasingly interconnected communities.

Acknowledgments

This work is supported by grants from the Program of the National Natural Science Foundation of China (31971037), the National Social Science Foundation of China (19BYY027), the Supervisor Academic Guidance Program of Shanghai International Studies University under Grant (2022113023), and Postgraduate Research & Innovation Program of Institute of Corpus Studies and Applications, Shanghai International Studies University.

Conflict of interest

The authors declare no conflict of interest.