The bilingual brain

This is a very interesting TEDx Talk about the “benefits of a bilingual brain” by Mia Nacamulli. – I only would like to point out that grown ups usually learn a new language in a very “conventional” way, which is rule-based (i.e. using books, learning grammar first), what leads to using one side of the brain only, like it is mentioned in this film/talk.

When adults learn a new language in the same spontaneous, memory based way like children, the brain activity is similar to the one of children who acquire a new language by involving both hemispheres. The approach is then less “rational” and more “emotional”. Language ability is measured in two parts: the active part – speaking and writing – and the more receptive part – listening and reading.

A balanced bilingual has a nearly equal ability in both (or all) the languages,  whereas most bilinguals use their languages in “various proportions, and depending on their situation, and how they acquired each language they can be classified into three general types”*: 

Compound bilinguals:

They learn the two languages, two linguistic codes, simultaneously in the same context where they are used concurrently, so that there is a fused representation of the languages in the brain. – This is the case when a child is brought up by bilingual parents, or parents with  two different linguistic backgrounds.

Coordinate bilinguals:

The person learns the languages in separate environments, and “works with two sets of concepts”, and words of the two languages are kept separate with each word having its own specific meaning. This happens for example when a child attends daycare or preschool in an additional language.

Subordinate bilinguals:

The person attained her bilingualism later in life. As a result, she often uses her primary language to subordinate the second language. The so called subordinate bilinguals or subsequent bilinguals  usually learned their additional language (it can be the second, third etc. language!) in a formal environment like school. – Please read our post about the difference between language acquisition and language learning

We can not see and sometimes not hear the difference between the kind of bilinguals. Thanks to recent studies in neuroscience and bilingualism we can tell more about how bilingualism affects the brain.
With regards to the CPH (Critical Period Hypothesis) it needs to be clarified that this hypothesis which became popular thanks to Eric Lenneberg’s Biological Foundations of Language in 1967, and later picked up by Noam Chomsky, has mislead some scholars. This hypothesis states that there are “maturational constraints on the time a first language can be acquired”, and “after this period language cannot be acquired in a natural fashion”, fact is that the study focused on abused, i.e. neglected children who had been deprived of first language in early childhood. And this hypothesis is valid for L1, the first language or languages, not the second or additional ones.
Although it is not clear if the deprivation of language input and stimulation in these children is the only reason for their language acquisition difficulties (Sampson 1997, 37), “it is not certain if children in cases of extreme deprivation have trouble learning language because they have missed their so-called “critical period” or if it is because of the extreme trauma they have experienced.” – This means that a person that is exposed to regular language input and stimulated to communicate in it will be able to acquire and learn a language no matter the age!
The main difference between adults and children acquiring/learning languages is that adults tend to have a more rational approach to learning additional languages in adulthood because the conventional way these are taught is more analytical, focusing on the structure of the language (grammar, rules, differences in phonology, morphology, syntax, vocabulary, prosody etc.), and does not focus on repeating words and sentences the way young children acquire languages! – Please read also this post about “The Earlier the Better?” or watch my video about it:



The approach is different and “more natural”. Of course, adults will try to connect all the new data with data they already know, i.e. the language structure of the other languages they already know, but an approach that doesn’t focus primarily on grammar and rules is proving not only more time efficient – because more engaging – but also more effective concerning the emotional understanding of the new language. 
What concerns the visible increase of brain density in bilinguals and multilinguals is a fact and one of the most quoted advantages of speaking multiple languages. The “involvement of the dorsolateral prefrontal cortex which plays a role in executive function, problem solving, switching between tasks and focussing while filtering out irrelevant information”, makes the brain of multilinguals more healthy and actively engaged. No matter when one learns another language: it’s never too late!  
On a side note: What is said about Alzheimer and Dementia in the aforementioned video is not only related to bilingualism. The same beneficial effect can be observed in people who engage their brain actively on a regular basis.
 * in linguistics we also use terms like simultaneous, additive, consecutive (or sequential), balanced, receptive, early, late and subtractive bilinguals, depending on the aspect we are focusing on. 

If you want to know how our brain changes if we speak two or more languages, I recommend you to watch (listen to) this video too:

About multilingualism or polyglots and their brain functioning, please watch Xaver Funk’s presentation Polyglot Science at the Polyglot Conference 2020

Further readings:

What is Different in the Bilingual Brain? An interview of Prof. François Grosjean and Prof. Ping Li

Hernandez, Arturo E., The Bilingual Brain, OUP, 2013
Lenneberg, Eric, Biological Foundations of Language. New York: John Wiley & Sons, 1967.


    • Jennifer, yes, it is… It requires quite some commitment and energy, but especially when you learn a new language that is related with one that you already know (like French and Italian or Spanish), it can help bridging between the two. Some consider it confusing because they mix the two languages for some time, but that’s a very typical phase that only shows us that we are making sense of what we’re learning. – What is your experience with learning languages so far? Are you learning one at the moment? Sorry, I’m curious… 😉

  1. Very interesting. . I love the information provided. My mother who is from Austria came to the US when she was 17. She learned english as a child in Austria. Recently, she was diagnosed with dementia. She is bilingual and has been since she was a child. When she is able to talk with her brother who is till in Austria, she is more alert and her memory seems to function better. Her thought process is more fluid and she is less frustrated. I wish I had retained the German that I was fluent in in high school. Glad it is not too late to go back and re-aquire it.

    • Sharon, what you’re saying about your mother being more alert when she talks German is wonderful! It actually confirms studies that are observing this with motoric activity and other degenerative diseases. What you can try to when with your mother is to put on some German music. If you don’t feel like singing with her, having it in the background could also trigger similar things like talking German. I would love to know what your observations and experience is with this! And yes, of course: you can always go back and reactivate what you learned or acquired earlier in life. I wish you all the best – bis bald 😉 ~ Ute

  2. Many years ago someone asked me when did I learn English. I was in a blank stare. I really could not remember. The person thought I was nuts. I said for real, I remember speaking Spanish as a child at home, and in school I could suddenly understand things in English. I don’t have an accent so I tend to confuse people a lot living in Miami. So fast forward today, I studied French heavily in high school and college, forgot how to communicate the level I learned by I can read it and understand if spoken slowly. I never studied Italian but the school I work in is an Italian center with one Italian immersion class in each elementary grade level taught by a native Italian. I teach them songs in Italian and thus I can understand most of the lyrics. I freaked my husband out once I was watching news in Portuguese, and yes I can understand plenty, but cannot speak it. I had some Brazilian friends and could understand them perfectly. Speaking of reactivating what you learned, for a season during college years I had lost the Spanish language quite a bit until I was asked to translate songs into Spanish from English, forced to speak it and write it… all came back to me. Years later I certified in Spanish Language, read, write, speak it now. All in all, I think I love and I’m fascinated by languages, acquisition and brain function.

    • That is such a fascinating journey of languages, Cecilia! I can understand your ways of learning/acquiring languages! Language attrition (or almost loss) is so frequent in multilinguals. If we don’t use the languages regularly and manage to foster them – learn new vocabulary and use it actively! – they become “dormant”… I’m very curious to know what you think of your level of competence in all your languages right now, today.

  3. Hi Ute, I am lead to believe that Spanish being a Romance language opens the door to all others. But….here goes. My native language is Spanish. I speak, read and write it fluently. If I don’t know a word (outside of daily speak) I go to the root (having studied one year of Latin in high school). English I’m fluent as well. I can translate from Spanish to English/English to Spanish simultaneously while the person is speaking. But…..throughout my day I think in English, count in English, alphabetize in English. I get angry in Spanish ahahahah.
    French I reached advanced conversational French in college, which included the rational approach, but because I have no one to communicate with I’ve lost it. I have managed to communicate with little Haitian children new to my school simple things but within a month they are already speaking English. Amazing! There goes my French!
    The Italian I’ve picked up just listening. I really can’t speak but I can read and decipher meanings given the Spanish/Latin relationship. Same with the Portuguese although it’s been a while. I did teach myself to decode the Korean language but thats it, I can sound it out but I know little vocabulary just a few phrases I can actually understand.
    So when I’m asked about language my first language is English because I was raised in the US since age 2, and Spanish is my native language, still there, very active. Helps to live in Miami. I watch a lot of foreign films. It tweaks you ear and brain. Oh, and I’m a Coordinate bilingual. Sorry for the long wind.

    • Cecilia, what you tell me about being immersed in English and doing everything in English is what is my situation at the moment (since many years already), but when I’m angry I can only express it genuinely in Italian 😉 I never learned Spanish but read scientific articles for my work. Italian, Latin and French helped me a lot with understanding. I can say a few words and sentences, but I would need full immersion to activate speaking. I am trying to learn Korean too, but it’s difficult when I only have “passive” resources. How do you learn it?
      I know it’s difficult to define our first language/ native language etc. because we can reach nearly native fluency also with a language that we learn later in life. I would say you are simultaneous early bilingual English-Spanish, no? I totally agree with “watching foreign films tweaks your ear and brain”! I do the same. Now I’m curious to know what films you’d recommend for Korean (ans Spanish) 🙂

    • Thank you, Cindy, for your feedback. There is a lot of research about this topic. I will write more about it soon; what would be of interest for you? Just trying to find out what to write first 😉

  4. Hi Uti,
    Interesting article, thank you.
    I’d just like to point out that when quoting the TedTalk video about what the dorsolateral prefrontal cortex does, you wrongly quoted it as “switching between tasks and focusing while filtering out relevant information”. As per the video, it states that the dorsolateral prefrontal cortex allows you to “[focus] while filtering out irrelevant information”. (4:20 in the video).

    Just wanted to help!! Thanks again

    • Thank you, Kelsey! I corrected the mistake! I’m happy you liked the article. If you would like to share more about this topic, please don’t hesitate to post links or further readings here in the comments. I’m updating this post regularly. – Thanks again!

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