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How Do Babies Become Bilingual?

You know that feeling when you get tongue-tied, and words come out as a jumbled mess?

Maybe you forget a word, or have mushy grammar, or your pronunciation is all wrong.

There are a lot of things to keep track of!

It seems like learning one language would be hard enough for babies, who already have

trouble eating and not spitting up everywhere.

But research has shown that infants are a lot more capable than you might think, especially

when it comes to language.

In fact, a lot of babies from bilingual families grow up fluent in both languages.

Many psychologists think language is what’s called an innate ability, or something we’re

born knowing how to do, like grasping objects and sucking on things.

Classic cute baby stuff!

So right from the start, babies are primed to learn a language – any language.

Most of us adults have trouble hearing subtle inflections in foreign languages.

Like, if you only speak English, it might be hard for you to hear the difference between

certain sounds in Thai or Russian.

But in their first few months of being alive, babies can tell really similar sounds apart.

To figure this out, lots of researchers have done studies where they pick a sound from

a foreign language and play it on loop for babies around four months old.

When the babies lose interest, the researchers switch to a new, similar sound.

Usually, these really young infants notice the difference and perk up somehow, like by

looking around or sucking harder on a pacifier.

But if scientists repeat this experiment around eight months later, one-year-old babies typically

ignore the second sound because they don’t notice a difference.

That’s probably because as they get older, their brain cells make connections that help

them focus on the sounds of their native language, and they get rid of unused connections related

to recognizing other sounds.

So, by the time an infant is one year old, its brain is already focusing on learning

whatever language it’s been exposed to most.

And, surprisingly, babies don’t need any special training to be bilingual!

But they need equal exposure to both languages.

Now, you might have heard that bilingual kids develop more slowly than their monolingual

counterparts, or are more likely to have speech delays.

But, according to the research, that’s just not true!

That even applies to babies who grow up with one spoken and one signed language – like

English and American Sign Language.

As they get older, these kids keep their languages separate thanks to their awesome perception

skills.

Just by watching faces and listening to verbal patterns, they’re able to figure out when

they should be speaking which language by around the time they’re three years old.

And when they intentionally switch from speaking one language to another, like talking to their

friends in English but to their mom in Cantonese, that’s called code-switching.

Now, even though monolingual and bilingual babies develop at the same rate, one study

from the University of Washington suggests that their brains process language a little

differently.

Psychologists used electroencephalograms, also known as EEGs, to detect electric brain

activity in some six-month-old monolingual and bilingual babies as they played recordings

of speech sounds in English and Spanish.

Babies in EEG caps?

Super adorable.

They found that monolingual babies caused a spike on the EEG whenever a mismatched sound

popped up, like a Spanish sound thrown in among a bunch of English sounds or vice versa,

which means they noticed a difference.

But bilingual baby brains didn’t notice when the languages switched.

When the same babies were 10 to 12 months old, though, the results changed:

The monolingual baby brains only responded when a sound in their native language interrupted

a string of foreign sounds.

But not the other way around.

And the bilingual babies went from not noticing a difference, to hearing both kinds of mismatches.

According to the researchers, this means that monolingual baby brains seem to solidify connections

faster, to get ready to speak their primary language.

But the bilingual baby brains stayed more flexible and didn’t develop that wiring

until later on.

Turns out that this flexibility can have some developmental perks, too.

One study published in the journal Science found that bilingual babies may be better

at learning rules and switching between them than monolingual babies.

In the study, one-year-old infants were taught that, when they heard a certain pattern of

sounds, they should look at a specific spot on a screen to see a fun toy.

When the psychologists changed the pattern and moved the toy picture, the bilingual babies

were better at figuring out the new rules and looking for the toy in the right places.

Multiple studies suggest that bilingual adults have similar benefits, like better focus and

ability to switch between tasks, and even less cognitive decline when they get older.

But this doesn’t mean all hope is lost if you’re not bilingual – it’s just one

path a human brain can take.

Our brains are really powerful, and even when you were a tiny, adorable baby, you were a

lot smarter than you might think!

Thanks for watching this episode of SciShow Psych!

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