- What do you see when
you look at this picture? Hopefully it's either a duck or a rabbit. Most of us can see both,
but not at the same time. We sort of switch back and forth. This is known as an ambiguous figure. You've probably seen lots of them. And they're often used by
psychologists and neuroscientists to study things like visual
perception and cognition. Recent studies have found
that bilingual children, those that speak two languages fluently, are more adept at switching back and forth between such images than
monolingual children. For a long time, people thought that
bilingualism was a handicap, that it stunted development
and language acquisition. Maybe that's because no
one really studied it until recently. Over the last several decades, research and experiments have suggested that being bilingual significantly
impacts brain function in ways that might surprise you. I'm Dr. Erica Brozovsky,
and this is Otherwords. (quirky music) - [Narrator] Otherwords. (quirky music) - Do you want to try and put that on? - [Erica] Dr. Maria Arredondo is a developmental psychologist who studies the cognitive
impacts of bilingualism in young children. - I'm an assistant
professor in the Department of Human Development and Family Sciences at the University of Texas at Austin. And I am the director of the child's lab. We study how bilingual children and infants are acquiring their languages and what are the mechanisms that are supporting the
acquisition of both languages. - So what drew you to the field
of bilingualism in general? - So I was born in Argentina,
my first language is Spanish, and I moved to the United
States when I was 12. I acquire a language very
quickly, in one or two years, but my siblings and my
parents struggled a lot. So I always became curious why some people are learning
their languages very quickly and why are others seem to struggle in bilingual acquisition. - [Erica] There are two
kinds of bilingualism, simultaneous and sequential. Simultaneous bilinguals
learn both languages at the same time in infancy while sequentials learn
their dominant language first and a second later in life. While a sequential bilingual
may maintain a similar level of proficiency, there are
fundamental differences in how these languages
are acquired and used. One of the most significant is phonetics. It's estimated that humans can make around
800 distinct verbal sounds, known as phonemes, like ch or oo or ss. Any individual language
will only use a few dozen, and the ones you don't
use, you can't really hear. For instance, r and l may sound distinct to English speakers, but the Japanese only
have one phoneme for both, and in French, there's
a sound between p and b that English speakers can't discern. But here's the amazing thing. Babies can hear all of these sounds. - [Maria] So from very early on, infants can distinguish
the different sounds in all the languages, but with time, they begin to specialize in the sounds for their own native language. - [Erica] Multiple studies suggest that infants under six months can perceive the whole
spectrum of phonemes. As they develop, they
focus only on those used by their native language and essentially lose the
ability to hear the rest. It's called perceptual narrowing. As you can guess, bilingual
children keep all the phonemes from both languages, but only if they learn both from infancy. Sequential bilinguals, those who learned a second
language later in life, almost always retain a perceptible accent, no matter how proficient they are in all other aspects of a language. There's pretty much just
that one narrow window to learn all the phonemes you'll use for the rest of your life. But if you're picturing all
these phonemes sloshing around like a bowl of alphabet soup, it's actually a lot more
organized than that. So can children distinguish
between the two languages? - Bilingual-raised
children can distinguish between their two languages very early on, during the first year of life. We know that they can do
that as soon as they're born. There are studies showing that neonates, they can distinguish between the languages that their mom spoke
while they were in utero. As they're acquiring both languages, they are beginning to
figure out on their own which sounds are for each language, but also what is the syntax
for each of their languages. - The two languages are
very clearly separated and delineated in a bilingual's
mind, which makes sense since they have different
sounds, rules, and rhythms. When they change from
one language to another, even mid-sentence, it's like
a mental switch is flipped. One language is given full attention and the other one is turned off, so as not to cause confusion. - [Maria] They're very aware
of their code-switching. So for instance, my niece, she will mix between
both of their languages when she's speaking to me because she knows that I am bilingual and that I am capable of understanding when she is code-switching, but she wouldn't do that to an
English monolingual speaker. - But how would an infant brain know that it's learning two
different languages? One possible answer is prosody, the patterns of rhythm in speech. For example, English is a stress-timed language, which means that the rhythm is
based on the important words and all the unimportant words are just jammed in between the beats. I'm gonna go the store,
I'm gonna buy some snacks, and then I'll come home. Spanish, however, is a
syllable-timed language where each syllable is
given more equal timing. Voy a ir al supermercado, a comprar unos bocadillos,
y ya vuelvo de regreso. Prosody is also influenced by word order. English and Spanish are both
subject-verb-object languages. The dog ate his bone. El perro se comió su hueso. SVO languages usually
have articles like "the" before the noun, giving it
an iambic sound pattern. The dog, el perro. My mother, me madre. Subject-object-verb
languages, like Japanese, place the article after the noun, which creates a somewhat
more inverse sound pattern. Kare ni Soko de - [Erica] It's possible
that even in the womb, a fetus may be able to pick
up on these distinct patterns and start to sort linguistic information into separate mental containers. How are the strategies
that bilingual children use to learn language different
from monolingual children? - We know that monolinguals,
around 18 months, they use mutual exclusivity,
which is a strategy in which they are mapping a
novel word to a novel object. So for instance, if you present
a child with two objects, one is a familiar object,
one is an unfamiliar object, and you provide a name that
they've never heard before, then they're going to map that novel name to that new object. But bilinguals, there's evidence showing that they're not relying
on mutual exclusivity as much as monolinguals. And that's because they know
that two labels are given to one object. There are other strategies
that bilinguals rely on when they're learning words, so we do know that they are
looking at audio-visual cues, the mouth of the speaker. The more that they look at the mouth, the higher their retention is when they are naming a new object. - As you can see, the mental
demands on bilingual children are pretty heavy, and it does mean that some language
milestones may show a delay when compared to a monolingual child, which makes sense considering
that the developing brain of a bilingual child
has double the workload. But, like a bodybuilder, that extra effort means extra muscle, neurologically speaking. - [Maria] In the brain, we see that bilinguals are
showing different activity during executive function tasks. The mechanisms that we are relying on are attention and inhibition. So with attention, we are
focusing on the language that's being in use right now, so I'm focusing on English
and I'm inhibiting my Spanish. - [Erica] That's why
bilingual children are better at tests involving ambiguous figures. It's easier and faster for
them to turn off rabbit and turn on duck. - [Maria] So the better your executive function abilities are, the better that your
academic abilities seem to be during the school years. What's fascinating about this work is that it's showing
that the brain is plastic and that experiences like
bilingualism can alter how the brain is organized. There is research showing that
bilingualism is associated with a delay in Alzheimer's diagnosis. With age, obviously, the
brain begins to deteriorate, but bilinguals are showing that this is a much slower deterioration. But what we still need
to try to understand is how these changes in
the brain are related to bilingual acquisition. And that's where the field is heading now. - That's not even mentioning the social and cultural benefits of bilingualism that are harder to test in a lab. The more people you can communicate with, the more opportunities life can offer and the richer your experiences can be. Unlike the cognitive advantages, these are available to simultaneous and sequential bilinguals, so it's never too late to benefit from learning a second language. It's estimated that humans
are capable, capable, capable. It's estimated that
humans are capable, cape. It's estimated that humans are capable, I can't even say capable. Cape. Starting from scratch.
