How speaking multiple languages changes your brain

There are many reasons to learn a new language — it might be for work, a love interest, or a personal interest in a region's culture or people.

Research shows that learning languages benefits your overall brain health too.

Learning a new language is like working out your brain. Just as muscles get stronger with physical training, neural pathways in the brain reshape when you learn a new language.

That's what neuroscientists mean when they say people who speak multiple languages process information differently than those who speak one language. But what really happens in the brain when you learn a new language, and does it make you smarter?

Language areas of the brain

Before we get to those questions, here are some basics about how language requires many different parts of the brain.

Language processing involves two key circuits — one for perceiving and producing sound, which forms the foundation of language, and another for selecting which language's sounds to use, said Arturo Hernandez, a neuroscientist at University of California San Diego, US.

"These circuits are rewired as we learn and switch between languages. It's about mapping sounds and deciding which language to operate in," Hernandez told DW.

We need sensory areas like the auditory cortex to process speech sounds, and we need the brain's expansive motor networks to coordinate the muscles involved in speech, such as those for controlling the tongue, lips and vocal cords.

This is true for all languages, but changes in 'higher processing' areas of the brain are needed to learn a new language.

For example, the Broca's area located in the frontal lobe is primarily responsible for syntax — the way we structure sentences. It helps construct grammatically correct sentences and understand sentence structure.

The Broca's area is also key for speech production and facilitates the motor control needed for articulating words.

Other brain regions like Wernicke's area play an important role in vocabulary comprehension and word retrieval. It helps in understanding the meaning of words and storing them in long-term memory.

Learning a new language physically changes the brain

A German study in 2024 measured the brain activity of Syrian refugees before, during, and after they learned the German language.

It found that people's brains rewired as they became more proficient in German.

'Brain rewiring' means that the brain's neuronal structures physically changed. This process — called neuroplasticity — is the mechanism which underlies learning.

Learning a new language therefore required new ways for the participants' brains to encode, store, and retrieve new linguistic information.

"Structurally, [learning a language] increases gray matter structure in areas related to language processing and executive function," said Jennifer Wittmeyer, a cognitive neuroscientist at Elizabethtown College in Pennsylvania, US.

Structural changes in the brain also change the way the brain functions as it physically changes the way neurons communicate. This so-called 'neural plasticity' helps you remember words faster, recognize new sounds better and improve pronunciation by controlling your mouth muscles.

"Functionally, [language learning] enhances connectivity between brain regions, allowing for more efficient communication between networks involved in attention, memory, and cognitive control," Wittmeyer told DW.

Learning languages as a child is an advantage

Studies show that we use the same brain networks for all languages, but the brain responds differently to our native language. One study found that brain activity in language networks actually decreased when participants listened to their native language.

This suggests the first language you acquire is processed differently in the brain with minimal effort, researchers say.

Research also shows it's much easier for young children to learn new languages than it is for adults.

Young children's brains are still in development and are more adaptable to neural plasticity and learning. Unlike adults, they don't have to translate from their first language, so they pick up sounds, grammar, and words more effortlessly.

"At an early age there's not as much rigidity in the brain. Adult brains are already structured around their first language, so a second language must adapt to existing knowledge rather than develop independently as it relies on previously established neural networks," said Hernandez.

Does learning a language make you smarter?

Some research does show that multilingualism improves cognitive abilities like memory and problem-solving abilities. But does this mean polyglots are smarter?

It's complicated, but probably not, said Hernandez.

"If somebody speaks more than one language, it increases their verbal repertoire. They have more words across all languages, more items, necessarily more concepts," said Hernandez.

But it's unclear if having a bigger vocabulary is due to a bigger cognitive reserve or just having more words stored in the brain's memory banks. And this isn't the same thing as intelligence.

To really test if polyglots are more intelligent, scientists would need to "find a task that's not related to language," said Hernandez.

So far, the evidence isn't very clear that polyglots perform better in tasks which aren't related to languages.

And scientists aren't sure if changes in cognitive skills in multilinguals are due to learning languages, or due to other factors like education or the environment they grew up in. There are too many factors involved in cognitive skills to isolate it to one factor like language learning, say researchers.

But regardless of whether better cognitive skills equals smartness, it's clear that learning new languages opens up new cultural experiences in your life.