WEBVTT

00:00:06.635 --> 00:00:12.495
¿Hablas español? Parlez-vous français? 
你会说中文吗？

00:00:12.495 --> 00:00:18.333
If you answered, "sí," "oui," or "会"
and you're watching this in English,

00:00:18.333 --> 00:00:23.469
chances are you belong to the world's
bilingual and multilingual majority.

00:00:23.469 --> 00:00:25.563
And besides having 
an easier time traveling

00:00:25.563 --> 00:00:27.471
or watching movies without subtitles,

00:00:27.471 --> 00:00:29.895
knowing two or more languages
means that your brain

00:00:29.895 --> 00:00:34.777
may actually look and work differently
than those of your monolingual friends.

00:00:34.777 --> 00:00:38.272
So what does it really 
mean to know a language?

00:00:38.272 --> 00:00:43.133
Language ability is typically measured
in two active parts, speaking and writing,

00:00:43.133 --> 00:00:46.985
and two passive parts, 
listening and reading.

00:00:46.985 --> 00:00:49.655
While a balanced bilingual has near equal

00:00:49.655 --> 00:00:52.377
abilities across the board 
in two languages,

00:00:52.377 --> 00:00:55.760
most bilinguals around the world
know and use their languages

00:00:55.760 --> 00:00:57.981
in varying proportions.

00:00:57.981 --> 00:01:01.612
And depending on their situation
and how they acquired each language,

00:01:01.612 --> 00:01:04.915
they can be classified into
three general types.

00:01:04.915 --> 00:01:07.767
For example, let's take Gabriella,

00:01:07.767 --> 00:01:12.007
whose family immigrates to the US 
from Peru when she's two-years old.

00:01:12.007 --> 00:01:13.823
As a compound bilingual,

00:01:13.823 --> 00:01:18.275
Gabriella develops two linguistic 
codes simultaneously,

00:01:18.275 --> 00:01:20.297
with a single set of concepts,

00:01:20.297 --> 00:01:22.165
learning both English and Spanish

00:01:22.165 --> 00:01:25.358
as she begins to process 
the world around her.

00:01:25.358 --> 00:01:29.162
Her teenage brother, on the other hand,
might be a coordinate bilingual,

00:01:29.162 --> 00:01:31.338
working with two sets of concepts,

00:01:31.338 --> 00:01:33.200
learning English in school,

00:01:33.200 --> 00:01:36.764
while continuing to speak Spanish
at home and with friends.

00:01:36.764 --> 00:01:41.845
Finally, Gabriella's parents are likely
to be subordinate bilinguals

00:01:41.845 --> 00:01:43.410
who learn a secondary language

00:01:43.410 --> 00:01:46.198
by filtering it through
their primary language.

00:01:46.198 --> 00:01:50.215
Because all types of bilingual people
can become fully proficient in a language

00:01:50.215 --> 00:01:52.723
regardless of accent or pronunciation,

00:01:52.723 --> 00:01:55.843
the difference may not be apparent
to a casual observer.

00:01:55.843 --> 00:01:58.619
But recent advances 
in brain imaging technology

00:01:58.619 --> 00:02:00.859
have given neurolinguists a glimpse

00:02:00.859 --> 00:02:05.714
into how specific aspects of language
learning affect the bilingual brain.

00:02:05.714 --> 00:02:09.009
It's well known that the brain's
left hemisphere is more dominant

00:02:09.009 --> 00:02:11.622
and analytical in logical processes,

00:02:11.622 --> 00:02:16.202
while the right hemisphere is more active
in emotional and social ones,

00:02:16.202 --> 00:02:20.075
though this is a matter of degree,
not an absolute split.

00:02:20.075 --> 00:02:22.883
The fact that language involves
both types of functions

00:02:22.883 --> 00:02:25.861
while lateralization develops
gradually with age,

00:02:25.861 --> 00:02:28.799
has lead to the critical 
period hypothesis.

00:02:28.799 --> 00:02:30.430
According to this theory,

00:02:30.430 --> 00:02:32.406
children learn languages more easily

00:02:32.406 --> 00:02:35.196
because the plasticity 
of their developing brains

00:02:35.196 --> 00:02:38.975
lets them use both hemispheres
in language acquisition,

00:02:38.975 --> 00:02:42.992
while in most adults, language 
is lateralized to one hemisphere,

00:02:42.992 --> 00:02:44.898
usually the left.

00:02:44.898 --> 00:02:47.684
If this is true, learning a language
in childhood

00:02:47.684 --> 00:02:52.480
may give you a more holistic grasp
of its social and emotional contexts.

00:02:52.480 --> 00:02:54.810
Conversely, recent research showed

00:02:54.810 --> 00:02:57.520
that people who learned 
a second language in adulthood

00:02:57.520 --> 00:03:01.423
exhibit less emotional bias
and a more rational approach

00:03:01.423 --> 00:03:03.811
when confronting problems
in the second language

00:03:03.811 --> 00:03:05.460
than in their native one.

00:03:05.460 --> 00:03:08.109
But regardless of when you acquire
additional languages,

00:03:08.109 --> 00:03:12.210
being multilingual gives your brain
some remarkable advantages.

00:03:12.210 --> 00:03:13.754
Some of these are even visible,

00:03:13.754 --> 00:03:16.338
such as higher density of the grey matter


00:03:16.338 --> 00:03:19.441
that contains most of your brain's 
neurons and synapses,

00:03:19.441 --> 00:03:23.504
and more activity in certain regions
when engaging a second language.

00:03:23.504 --> 00:03:26.889
The heightened workout a bilingual
brain receives throughout its life

00:03:26.889 --> 00:03:31.334
can also help delay the onset of diseases,
like Alzheimer's and dementia

00:03:31.334 --> 00:03:33.225
by as much as five years.

00:03:33.225 --> 00:03:35.943
The idea of major cognitive 
benefits to bilingualism

00:03:35.943 --> 00:03:37.519
may seem intuitive now,

00:03:37.519 --> 00:03:40.507
but it would have surprised 
earlier experts.

00:03:40.507 --> 00:03:44.194
Before the 1960s, bilingualism
was considered a handicap

00:03:44.194 --> 00:03:45.999
that slowed a child's development

00:03:45.999 --> 00:03:50.652
by forcing them to spend too much energy
distinguishing between languages,

00:03:50.652 --> 00:03:54.089
a view based largely on flawed studies.

00:03:54.089 --> 00:03:56.178
And while a more recent study did show

00:03:56.178 --> 00:03:59.415
that reaction times and errors increase
for some bilingual students

00:03:59.415 --> 00:04:01.427
in cross-language tests,

00:04:01.427 --> 00:04:03.825
it also showed that the effort
and attention needed

00:04:03.825 --> 00:04:06.776
to switch between languages
triggered more activity in,

00:04:06.776 --> 00:04:11.465
and potentially strengthened,
the dorsolateral prefrontal cortex.

00:04:11.465 --> 00:04:14.142
This is the part of the brain
that plays a large role

00:04:14.142 --> 00:04:18.971
in executive function, problem solving,
switching between tasks,

00:04:18.971 --> 00:04:22.644
and focusing while filtering out
irrelevant information.

00:04:22.644 --> 00:04:26.480
So, while bilingualism may not
necessarily make you smarter,

00:04:26.480 --> 00:04:30.897
it does make your brain more healthy,
complex and actively engaged,

00:04:30.897 --> 00:04:33.422
and even if you didn't have 
the good fortune

00:04:33.422 --> 00:04:35.651
of learning a second language as a child,

00:04:35.651 --> 00:04:37.794
it's never too late to do 
yourself a favor

00:04:37.794 --> 00:04:40.572
and make the linguistic 
leap from, "Hello,"

00:04:40.572 --> 00:04:43.559
to, "Hola," "Bonjour" or "你好’s"

00:04:43.559 --> 00:04:48.081
because when it comes to our brains
a little exercise can go a long way.