The Effects of Multilingualism on Brain Structure, Language Control and Language Processing

This chapter reviews a small but growing body of research that examines neuroplasticity stemming from multilingualism, specifically discussing some similarities and differences in brain structure and function stemming from in processing three or more languages, as a departure from bilingualism. The evidence comes from studies using magnetic resonance imaging to examine patterns of grey matter structure across cortical and subcortical regions, and aspects of white matter microstructure. This chapter also highlights the functional activation and temporal information of various processes that occur during language processing in multilinguals, while accounting for the influence of language background factors. It then discusses conflicting and agreeing evidence in the literature and attempts to consolidate the findings with suggestions based on contemporary frameworks such as the Dynamic Restructuring Model (Pliatsikas, 2020). In closing, the chapter highlights gaps and pose questions for future research directions in the field of multilingualism and neuroplasticity

Language identity in the Singaporean context

This study aims to validate a survey tool and visualisation technique that enables us to obtain a detailed “language fingerprint” for individuals, which would reflect the linguistic diversity in Singapore - a feature of the bilingual context which is often overlooked. This tool would chart out the language background of individuals, and reveal a unique language identity that differs from person to person. The information to be collected includes the languages used by individuals, the duration of exposure to the languages, self evaluations of language proficiency, language preferences, how they feel about their languages, as well as contexts in which the languages are used. The study will also document who spoke which languages how much to the participants as they were growing up, allowing a measure of how language input in childhood contributes to the individual’s language identity. Taken together, this study identified patterns of language “knowledge” of Singaporeans, as well as their consumption behaviors in relation to reading, watching, listening and writing. It is also found that early language input in the form of age of acquisition (AoA), language mix and years of use are significant predictors of language proficiency in an individual’s later years, and do correlate to consumption behaviours in the areas of reading, watching and listening.Bachelor of Art

Multilinguals reveal the brain’s capacity for lifelong transformation

Think the human brain stops transforming in adulthood? You might want to think again! Contrary to popular belief, the human brain continues to change throughout our lifetime in response to the various experiences that we acquire. One such experience is the use of more than one language – an activity many of us already engage in in our daily lives. Join us in this chapter as we debunk the misconception of a static adult brain and delve into the evidence of multilingualism-induced neuroplasticity

Subcortical restructuring as a function of multilingualism: Insights from monolinguals, bilinguals, trilinguals and quadrilinguals

Subcortical structures implicated in language control and processing adapt structurally with increasing language experience. However, the adaptation patterns across different subcortical structures remain unclear. Previous findings from bilinguals and multilinguals reveal renormalisation patterns, lending support to the Dynamic Restructuring Model (Pliatsikas, 2020). These patterns comprise of increasing volumes during the initial stages of language learning, and subsequent reductions as experience increases. T1-weighted images from 14 English monolinguals, 14 bilinguals, 14 trilinguals, and 14 quadrilinguals were obtained. The volumes of five subcortical regions implicated in language control and processing were compared amongst the groups. The findings showed group differences for every structure - caudate nucleus, nucleus accumbens, putamen, globus pallidus and thalamus. Complex patterns were unveiled for each structure, suggesting expansions and renormalisations that differ in trajectory for each group. These findings highlight the dynamic progression of subcortical adaptations, and support the notion of structural renormalisation as language experience grows