Dr Marco Calabria is giving a lecture in Barcelona for Deep Dive on Thursday 17 December 2026. Deep Dive Lectures is now a reference lecture series in Barcelona: professors and experts give English-language talks in Barcelona bars. Someone who really knows their subject talks for about fifty minutes, and then everyone stays to discuss it over a drink. We are very happy he is giving this lecture in Barcelona for Deep Dive, and a few tickets are still left, so come along.
Calabria is a neuroscientist and associate professor of neuropsychology at the Universitat Oberta de Catalunya (UOC) in Barcelona, where he is a member of the NeuroADaS Lab. He holds a doctorate in psychobiology from the University of Padua and began as a clinical neuropsychologist in Brescia, Italy, working with patients with neurodegenerative diseases, including projects that used magnetic brain stimulation as a treatment for Alzheimer's. From 2009 to 2019 he was a researcher at the Center for Brain and Cognition at Pompeu Fabra University, funded by Spain's Juan de la Cierva and Ramón y Cajal programmes. He studies what happens to language in bilingual patients with Alzheimer's, Parkinson's and aphasia, and whether bilingualism protects the ageing brain. He has led three national research projects for Spain's State Research Agency and is an associate editor of the journal Bilingualism: Language and Cognition. His current project, BILiARD, looks at data from 2,700 people from the Barcelonaβeta Brain Research Center to find out which kind of bilingualism, if any, really helps.
His lecture, "Does Speaking Two Languages Protect Your Brain?", starts from a striking fact: nearly half of all dementia cases could be prevented or delayed by things within our control. So if you spend your days switching between Spanish, English and maybe a bit of Catalan, are you also training your brain to age better? These five answers are a preview.
Five questions he has been asked before, answered with his own published words. Some were given in Spanish or Catalan and are translated here.
The prevalence of dementia in countries where more than one language is spoken is 50% lower than in those regions where the population uses only one language to communicate.
In our case it was not so much prevention, because the people we studied already had the disease. But we did see that it delayed the onset. After studying people with mild cognitive impairment and people with Alzheimer's, we concluded that in those who practised active bilingualism, the symptoms of cognitive decline, like memory loss or the ability to find your way, appear years later.
We saw that the people with a higher degree of bilingualism received a diagnosis of mild cognitive impairment later than those who were passive bilinguals.
Sources: UOC News, 17 Sep 2020 (English original); 20minutos, 28 Sep 2020 (translated from Spanish).
Active bilingualism is when you actively use both languages, you regularly switch from one to the other, and you have high proficiency in both. In people who know a second language but don't use it in their daily life, the effect is not the same.
Bilingualism is not one thing. It includes the age at which you learned the second language, how much you use it, how well you speak it, and how often you switch between your two languages. That makes a simple, binary split between monolinguals and bilinguals make little sense.
We have seen that the more you use both languages and the better your language skills, the more neuroprotective advantage you have.
Sources: 20minutos, 28 Sep 2020; The Conversation (Spanish edition), 20 Sep 2020, both translated from Spanish; UOC News, 17 Sep 2020 (English original).
Switching from one language to another is, for our brain, like switching from one task to another. It trains it. People sometimes ask whether this works only for similar languages, like Catalan and Spanish. Compared with studies of English and French in Canada and other languages, the positive effect is more or less the same. My conclusion, for now, is that the benefit does not come from the languages being more or less similar. It comes from using them and switching from one to the other. That is what really trains our brain.
In our research, active bilinguals did better than passive ones on tasks that involve handling conflicting information. Everything points to the active use of two languages giving you more efficient executive control. And, as theories of cognitive reserve suggest, high cognitive efficiency may be able to compensate for the deficits caused by a neurodegenerative disease.
In the context of neurodegenerative diseases, this system could offset symptoms. So, when something is not functioning well due to the disease, the bilingual brain has efficient alternative systems for resolving the problem.
Sources: 20minutos, 28 Sep 2020; The Conversation (Spanish edition), 20 Sep 2020, both translated from Spanish; UOC News, 17 Sep 2020 (English original).
In 2004, Ellen Bialystok and colleagues at York University in Canada published a study that became very famous for suggesting that bilingualism delayed the diagnosis of Alzheimer's. They compared 184 patients, half bilingual and half monolingual. Bilinguals received a diagnosis of Alzheimer's about four years later than monolinguals. Others have replicated similar results in bilingual communities in India and Scotland.
But many researchers have also failed to show that speaking two languages protects against cognitive decline. According to some reviews, around 40% of studies show no benefit of bilingualism in delaying the onset of neurodegenerative diseases. That is not surprising, because the research on bilingual advantages in healthy people is not consistent either, and in several studies the effect is tiny.
So the crucial question is whether something shapes the benefit of speaking two languages. That would explain why the effect is sometimes robust and sometimes not.
That is what we are testing now. We'll compare different types of bilingualism and, based on cognitive tests and brain imaging, determine whether there really are advantages, and in which areas. Catalonia is an opportunity to study a population with a linguistic experience that is almost unique in the world. The social bilingualism that exists here is found in few other countries, with exceptions such as India or part of Canada.
Sources: The Conversation (Spanish edition), 20 Sep 2020 (translated from Spanish); UOC News, 19 Feb 2025 (English original).
It is one of the questions we are asking ourselves now, but the truth is that there is very little research on it at the moment, at least where neurodegenerative diseases are concerned. The effect of bilingualism, which lasts a lifetime or many years, is one thing. Learning a second language as an adult is another. You can't compare them.
What we always recommend is that if you learn a language, even late, you at least use it actively. If not, it will not bring many benefits. But beyond any benefits for particular diseases, learning a language is always positive at any age, because it helps keep the mind active, keeps you motivated and raises your self-esteem.
Sources: 20minutos, 28 Sep 2020 (translated from Spanish); UOC News, 19 Feb 2025 (English original).
The message that will need to be delivered is that speaking more than one language is beneficial as people get older, and that this needs to be fostered from an early age.
Doors 18:30 · Lecture 19:00 · Venue to be announced · In English