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[♪ mysterious/mystical music]
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Man: It is probably the most amazing thing you do,
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and it defines you as being human.
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Woman: And you do it with ease,
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so much so you barely notice you're doing it.
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Toddler: Apple. Parents: Yeah! Apple!
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Woman: Your ability to talk.
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Man: Or more precisely,
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the way you use language.
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[Speaking in different languages]
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Woman: Language.
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Robotic Male Voice: Hi, baby.
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Narrator: From the moment we're born,
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we have language in our lives.
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Robotic Female Voice: Hi, baby.
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Narrator: A unique ability that defines us
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as human.
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Man 2: I can walk up to someone I don't know
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and I can make a sequence of noises
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that I've never made before
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by pushing air through my mouth.
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I will take a thought in my head
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and make it go into their head.
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And that's an incredible trick.
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[Dog barks]
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Narrator: Other animals may use sounds
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to communicate.
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We're the only ones on the planet
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who can talk.
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Woman 2: Speech and language distinguishes us
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from all other species.
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We are not only using words
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to be able to express ourselves,
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but we're really expressing
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our thought processes that are unique to ourselves.
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Narrator: For most of us,
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it just happens.
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Woman 3: It's such a sophisticated skill,
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and yet children learn it so easily
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with minimal effort at all.
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Girl: That's bubby.
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Woman 3: And when you start thinking about it
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it's quite miraculous how the brain does it.
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Narrator: But despite decades of research,
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how we learn to talk remains a mystery.
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How did this ability evolve?
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Why is it uniquely human?
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And is it something we're born with
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or something that we learn?
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Man 2: It strikes me as surprising and odd
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that we know an enormous amount
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about for example,
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the first fractions of a second
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in the history of the universe,
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but we really know very little at all
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about what makes us human
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and where language comes from.
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Toddler: I fell down.
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Daddy, I don't...
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[Toddler oohing and ahhing]
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Narrator: The wonder of language
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may not yet be fully understood.
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[Baby cawing and cooing]
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Baby: Ca. Ca-ca. Car-car.
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Narrator: But how we start to talk
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is now being observed minute by minute
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for the first time.
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Cognitive scientist Deb Roy,
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realized that to discover
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how a child learns to speak,
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he'd have to be to see and hear them
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24 hours a day.
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His solution was to take the extraordinary step
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of turning his own home into a language laboratory.
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And his guinea pig was his own son.
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[Toddler undecipherable]
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Roy: My wife and I were expecting our first child
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and we had many conversations around
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you know, would this possible?
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Could we set up our home as an observation space
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and actually capture this kind of
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rich longitudinal record of
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our own child's development from birth?
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And that's what we set up to do.
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Narrator: And so was born the speech home project.
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The most ambitious language observation experiment
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ever seen.
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Cameras and microphones recorded every second
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of Deb's son's life
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from the moment he was born
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until he was 3 years old.
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Capturing in precise detail the process
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of how we learn to talk.
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Son: Ba. Boo. Boo. Ba. Boo. Booba. Boobal.
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Roy: Blue ball, yeah.
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Narrator: From the earliest unintelligible babble
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to the emergence of a very first word.
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Wife: You want it?
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Toddler [whines]: Ba.
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Roy: Apple.
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Toddler: Apple. Parents: Yeah! Apple.
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Roy: My interest going in was
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really to understand the earliest stages
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of languages formation.
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And the typical development stages in language
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a child will go from babbling
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to using single words
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usually as a complete request and descriptions.
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And then, from that they will start
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what's called a two-word stage
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where they'll put two words together
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like "more milk,"
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and from that very quickly more complex
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grammatical structures emerge.
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My focus and my aim was to capture
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the phase up to the two word utterance.
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And that could happen anywhere
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between 2nd and 3rd birthday.
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It turned out my son was an early talker,
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so by the time his 2nd birthday arrived
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we had the main data set we wanted.
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Narrator: By the time recording was complete,
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more than 240,000 hours of information
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and 16 million words had been collected.
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Roy: It's a lot of data,
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but in it's raw form,
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it's useless.
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And so, the challenge is this now sets up for us
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is how to start extracting the right kind
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of metadata.
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Transcripts of who said what.
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Annotations of where those people were.
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Annotations of how they're moving
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and the relationships that they were in
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as they were speaking.
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And these are the tools that we're now building
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to analyze the raw data,
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and from that we're starting to see some early
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insights into the patterns of language development.
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Narrator: Despite the mountains
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of video footage,
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Deb Roy is already uncovering
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the intricate effect daily life
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has on language development.
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It seems cooing to your baby
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is not just instinct,
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it's essential.
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In the months leading up
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to their son's first words,
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he and his wife unconsciously
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simplified their speech.
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Then as their son's own speech develops,
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they began to use longer sentences again,
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mirroring the child's own development.
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Toddler: Green car.
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Roy: What's that over there?
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Over there. That ball.
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Toddler: Gren bal.
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Roy: Ooohhh.
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Narrator: For the very first time,
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the analysis has also enabled
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Deb to piece together the precise emergence
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of individual words.
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Charting how a new word is born.
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Mother: Okay, water. Wa-ter.
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Toddler: Ga-ga-ga-ga?
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Roy: So, my son around his first birthday
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started using the sound "ga-ga"
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to indicate "water."
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And then over the next several months,
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learned to slowly approximate
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the proper speech form.
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Mother: Water.
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Roy: Just like time lapsed video
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lets you capture a flower blossoming,
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what we're going to hear
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is the blossoming of a speech form.
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Mother: Okay, water. Wa-ter.
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Roy: Water?
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Roy: Water?
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Mother: Water.
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Roy: That's water.
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Narrator: It will takes years for Deb Roy
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and his team to analyze all of the data.
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But buried within this footage
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are the secrets of how we learn language.
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If the patents can be unlocked,
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then once this remarkable project is complete,
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we will have the clearest understanding yet
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of how a child achieves the remarkable feat
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of learning to talk.
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[♪ mysterious/mystical music]
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Woman 1: By the time a child is 5,
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they'll know as many as 5,000 words.