How does bilingualism reshape the brain?

There is a good amount of evidence to suggest that learning and using more than one languages can affect the function of the brain, with some researchers even proposing a general cognitive advantage for bilinguals, especially in older age. Until recently less was known about how these cognitive effects might be reflected in structural changes in the brain. However, since the seminal paper by Mechelli et al. (2004), and with considerable advances in MRI technology over the past 15 years, a growing number of recent studies have repeatedly shown the effects of bilingualism in both major parts of the brain, the grey and the white matter.

The grey matter consists of the cell bodies of our brain neurons, where most of information processing takes place, which are organised around the surface of the brain. The white matter on the other hand consists of the axons of our neurons, i.e. the part of the cell that provides communication with the surrounding neurons. The axons converge and interconnect underneath the grey matter, forming the white matter. We call it white matter because the axons are wrapped in a fatty layer, the myelin, which ensures better neuronal communication – the way information is transferred around the brain. The myelin functions as an “insulation” that prevents information “leaking” from the axon during transfer. Any structural changes in the grey matter are typically interpreted as a reorganisation of the affected brain region in order to accommodate and process new information, whereas any changes in the white matter are interpreted as reinforcement of white matter tracts in order to provide more efficient communication between brain areas, esp. under increased cognitive demands.

The experience of bilingualism ticks both boxes: a) It involves learning and processing of two, instead of one, linguistic systems, including phonological, semantic, lexical, grammatical and pragmatic information; b) it involves increased cognitive demands, esp. since both languages are now thought to be active at any time, so using one language entails actively suppressing the other one. None of these processes apply to monolingual speakers of a language, so it is only reasonable to expect that bilinguals will demonstrate structural changes in both the grey and white matter of the brain, when compared to monolinguals.

This is indeed the case, as demonstrated by research published in the last decade or so (for comprehensive review papers, see here and here). Recent work at the Bilingualism in the Brain lab at the University of Reading has provided even more evidence that learning and using a second language has an impact on the structure of the brain. A 2014 study revealed that bilinguals have greater grey matter volume in the cerebellum, a part of the brain involved in many cognitive functions, including linguistic ones. Moreover, the amount of grey matter in the cerebellum of bilingual participants correlated positively with the speed by which they performed a grammatical task; in other words, the bigger the grey matter volume in the cerebellum, the more efficiently they performed the task. No similar effects were observed in monolingual speakers, suggesting that the cerebellum might be a key area in the acquisition and processing of a non-native grammar.

A more recent study (Pliatsikas et al., 2015) showed that bilingualism also affects the integrity of the white matter of the brain. More specifically, it was shown that highly proficient non-native speakers of English who had lived and worked in the UK for an average of 7.5 years, had enhanced structure (expressed as increased myelination) in a number of white matter tracts that are involved in linguistic processing, among other functions. It is very likely that enhanced white matter facilitates cognitive processing, so the observed structural effects might be linked to the suggested cognitive benefits of bilingualism; however, that study did not include any cognitive tasks that would answer this question. Nevertheless, it is important to know that the observed structural effects almost mirror the pattern of changes observed in a group of elderly lifelong bilinguals in a previous study. This suggests that enhancement of white matter, and any benefits that may come with it, do not necessarily require lifelong bilingual experience, but immersive experience, i.e. active usage of both languages.

It is obvious that this is still a young but promising field of research. A thorough overview of the existing evidence reveals that factors that have not been systematically controlled yet might be crucial to explain the observed effects. These factors include language proficiency, immersion in a bilingual environment, age of acquisition of the additional language, socioeconomic factors, and so on. Currently ongoing and planned projects in our Bilingualism in the Brain lab look at exactly those factors, while at the same time aim to provide a link between the effects of bilingualism on cognition and on brain structure. This will allow us to eventually build a comprehensive theory about the potential benefits of bilingualism, especially in older age.

L2 Fluency Workshop

Centre for Literacy and Multilingualism (CeLM) and the Department of English Language and Applied Linguistics at the University of Reading were delighted to host a BAAL-Routledge L2 fluency workshop on Thursday 15th October 2015. The 25 delegates attending the event included PhD students, early-career and experienced researchers in second language acquisition and multilingualism traveling from around the country to participate in the workshop. The workshop included training in CLAN and PRAAT with hands on activities, a poster session, a panel discussion and a surgery slot.

The positive feedback we have received so far clearly suggests that the event has been very successful particularly in terms of training PhD students, consolidating the current understandings of the L2 fluency, contributing to the agenda for future research in this area and creating a community of practice among students, practitioners and researchers interested in L2 fluency.


The workshop was held at the historical venue of London Road Campus of the University and included lunch and coffee breaks offering networking and discussion opportunities to the delegates. Dr Clare Wight, who is Director of Bilingualism Matters at Reading and a member of the Steering Committee at CeLM, was the leader of the workshop. Dr Parvaneh Tavakoli was co-leading the event, and Professor Jeanine Treffers-Daller, Dr Louise Courtney and Mrs Anne-Marie Hunter ran the training sessions. We would like to acknowledge that the workshop was financially supported by CeLM funding and a loan from BAAL-Routledge seminar series.



CeLM protests against Exam Boards’ withdrawal of languages exams

With the introduction of new GCSE and A level specifications for languages from 2016 (for French, German and Spanish – 2017 for other languages) Exam boards have announced their intention NOT to redevelop qualifications in a range of small-entry languages, such as Bengali, Modern Hebrew, Panjabi, Polish; Dutch, Gujarati, Persian, Portuguese, Turkish (A-Level) and Dutch, Gujarati, Persian, Portuguese, Turkish (GCSE). There are rumours that also Arabic, Modern Greek, Japanese and Urdu may not be redeveloped.

The main reasons given by Awarding Bodies are mainly dictated by budget. According to them a) a small number of entries means that it is not cost-effective to redevelop the qualifications under the new, tighter assessment requirements, and there are difficulties in the statistical underpinning of grade boundaries; b) the more rigorous conditions attached to the new A-level specifications, and the need to teach and assess cultural content as well as language skills; c) difficulties sourcing examiners and other experts.

In a multilingual society, these short-sighted reasons must be strongly challenged and vocally rejected.

Firstly, these reasons do not take into account figures and facts. These languages are currently taught both in mainstream state and independent schools, in adult and further education, as well as in supplementary schools provided by local communities. Candidates include a mixture of bilingual native speakers, learners who have experienced some ‘background exposure’ to the language, and those who have learnt the language from scratch in schools, colleges or adult education contexts. In 2014, nearly 4000 candidates sat the affected languages at A level: with the exception of Urdu, Gujarati, Greek and Bengali, entries for all the affected languages have increased since 2004. According to research by the National Resource Centre for Supplementary Education (representing 922 schools teaching over 67,000 pupils), these reforms will affect 59% of supplementary schools teaching a language (in addition to the 13% whose languages already lack a qualification).

Secondly, the decision by the Awarding Bodies would have serious social, cultural and economic implications for the future supply of language skills that Britain needs, as remarked by the All-Party Parliamentary Group on Modern Languages in its Manifesto for Languages (2014). The decision would also have particular implications for schools which teach or wish to develop the teaching of a more diverse range of languages; communities which speak or learn the languages in which examinations are being withdrawn; individuals who wish to learn them. Briefly, this decision would be highly detrimental for individual cognitive improvement, community development, and social mobility.

CeLM – Reading strongly deplores the Exam Boards’ agenda. We strongly believe that more (and not less) resources should be allocated not only to generate new insights into the working of the multilingual mind as well as new perspectives on how literacy skills can be further in monolinguals, bilinguals and multilinguals, but also to sustain and support bilingual and multilingual families, to build a new sense of community in a multilingual world, and to promote equality and equal opportunities in our society.

Launch of the CeLM

On 3rd September 2013 we launched the new Centre for Literacy and Multilingualism (CeLM) at the University of Reading. Of course there are many Centres of Bilingualism and Multilingualism in the UK, as well as in, for example, Norway, Spain and the US, and they are already pursuing research into language learning, language processing or language teaching in bilinguals and multilinguals. So readers might wonder why we need another Centre of this kind which brings together researchers in the fields of linguistics, psychology, neuroscience and education.

The main reason for bringing researchers together in this Centre is that in particular in the UK, there is a great need for raising awareness about the fact that multilinguals are an asset and a resource. As the British Academy Report Multilingual Britain shows, we need more data to fully understand the nature and the extent of multilingualism in the UK. Policy makers, teachers and bilingual families do not always realise what the advantages are of knowing more than one language. There is more and more evidence that bilingual speakers have cognitive advantages over monolinguals because bilinguals juggle more than one language on a daily basis. Switching between languages is gymnastics for the mind, as Ellen Bialystok once put it. Bilinguals can shift more easily between tasks and focus on the relevant information in tasks, ignore what is less important. They can also be more creative and flexible than monolinguals. People who can speak and write in two or three languages are also extremely valuable on the job market, because of their ability to think outside the box. Bilinguals can open new business opportunities for business in the UK, because they have links to companies in other countries and can speak the languages of new customer groups.

While there are many studies about bilinguals, we know much less about the ways in which multilinguals process language, and we know hardly anything about the cognitive advantages of being able to read and write in a range of languages. Researchers in CeLM will focus in particular on the interface between literacy (being able to read and write) and multilingualism. Does it become easier to learn a third language when you already know two? We think that is the case, but more evidence is needed. We also hope to communicate our findings more efficiently to policy makers, families and practitioners in education and health care as we know we can only make a difference to society if we are successful in communicating our findings to a wider audience. So do follow us on our blog. You will be the first to know about our findings.


Jeanine Treffers-Daller

Director of CeLM