Baby Kanzi was recently adopted, and adjusting
to life in his new home. His mother was working with a language coach
to learn some English, and Kanzi usually came along, though he didn’t appear to pay much
attention. But the language coach noticed that he seemed
to be picking up on how to communicate, just by watching his mother’s lessons. Oddly enough, it appeared that he was picking
things up faster than his mom. For example, the phrases “you tickle”
and “tickle you” meant two different things, and Kanzi’s mom, she was having a hard time
understanding that syntax. But one day Kanzi was hanging out, playing
with stuffed animals, and the coach asked him to make the dog bite the snake. Kanzi
put the snake in the dog’s mouth, like it was no big deal.
It was a really big deal. Because Kanzi is a bonobo.
He’s actually a language superstar, even among the elite research primates, like Koko
the Gorilla. Kanzi is the first ape to demonstrate that language can be acquired spontaneously
through observation, without planned training, and the first to show a rudimentary understanding
of grammar, syntax, and semantics. Again, really. big. deal. Especially because
for years humans have proclaiming that it’s language that sets us apart from other animals. But are we really alone? Turns out, that question keeps getting more
and more complicated. Technically we define language as a set of
spoken, written, or signed words and the way we combine them to communicate meaning. If we change that definition to include the
use of complex grammar, then maybe we are alone.
But if language is simply the ability to communicate through a meaningful sequence of symbols,
as I might do while looking for a bathroom in Sweden, or Kanzi does when she’s asking
to roast marshmallows, well then welcome to the club, apes! [INTRO] We communicate, in part, by engaging our brains
and bodies to make sounds that let us transfer thoughts from our brain to other people’s
brains. But of course language is more than just making
air vibrate with sound. I can communicate by moving my hands, which you might have noticed
I do pretty frequently. Or by using visual symbols.
All of these forms of language allow us to comprehend things we’ve never actually witnessed,
and exchange information with each other quickly and effectively to, you know, get a job, or
be a friend, or use a metaphor. It’s hard to imagine a fulfilling life without some
kind of language. Humans have nearly 7,000 different languages,
and no matter how different they sound, we can break down their basic structure in the
same way, using the same three building blocks. The smallest of them are phonemes. These are
very short, distinctive sound units–like a, t, ch, sh, f. Like stuff like that. English
uses about 40 of them. Phonemes go together to make morphemes, which
are the smallest units that carry meaning. This can be words, or parts of words, like
a prefix or suffix. For example, the word SPEECH is a morpheme that contains four phoneme
sound units– s/puh/eee/ch. From there you can arrange morphemes into
your language’s grammar, or system of rules allowing you to say the things that you want
to say! So those 40 English phonemes give us over
100,000 morphemes that produce the more than 616,000 words in the Oxford English Dictionary,
which can then be arranged into an infinite number of sentences, paragraphs, Wu-Tang lyrics,
or Shakespearean plays. And just as the structure of language starts
small, so does how we learn language. And we start very young.
The word infant comes from the Latin infans, meaning “not speaking”– but as early
as four months, they can recognize differences in speech and start to read lips, matching
mouth movements with their corresponding sounds, like ah ee eye oh ooo.
And even at this age, you gotta watch what you say about kids in their presence, because
this also marks the beginning of receptive language, or the ability to understand what’s
being said both to, and about us. Soon that receptive language blooms to accommodate
productive language, when instead of just understanding other people, babies start developing
the ability to produce words. Of course that takes a while, but in the meantime,
they get a lot of practice babbling. Beginning at about four months they start to make all
sorts of sounds, although you may get a da-da or ma-ma, babbling is NOT an imitation of
adult speech. In fact, it typically includes sounds from many different languages, and
a stranger couldn’t tell if a kid was Italian, or Kenyan, or Korean, just by the sound of
her babbling. Similarly, deaf babies watch their parents
signing and start babbling with their hands. By about ten months, that babbling morphs
into something that starts to make sense, and ma-ma probably really means Mama.
Now, without exposure to other languages, a child will actually lose the ability to
both hear and create particular tones and sounds that aren’t part of his or her household
language. So, someone who speaks English around the
house soon won’t be able to differentiate between certain phonemes in Mandarin if they
heard them, for instance, or between aspirated and non-aspirated consonants in Hindi.
By the time they’re mowing down their first birthday cake, most kids will be entering
the one-word stage of language development. They now know that sounds carry specific meanings,
and can connect the sound “dog” to that furry thing across the room.
By around 18 months, their capacity for learning new words jumps from about one a week to one
a day, and by the time they’re two, they’re probably speaking in two-word statements.
These choppy sentences are a kind of like telegraphic speech — they sound like clumsy
texts or old-school telegrams, using mostly nouns and verbs. Want juice. No pants. That
kind of stuff. These little sentences make sense, and they
follow the rules of their language’s syntax. For example, an English speaking child would
put an adjective before a noun, black cat, while a Spanish-speaker would reverse that,
gato negro. From there the average kid is soon uttering
longer phrases and complete sentences, refusing to put pants on, and demanding more crackers. Most humans hit these same milestones during
their language development, but there are competing theories about how our infant babbles
turn into complex sentences, and how we acquire language.
You’ll remember B.F. Skinner, the pioneering behaviorist who brought us learning through
reinforcement. He believed language was a product of associative principles and operant
conditioning. Skinner argued that a kid learned to associate words with meanings largely through
reinforcement. So in the Skinner model, for example, if baby
Bruno says “mmmm” and his mother gives him some milk, he’d find that the outcome–both
the milk and the attention– rewarding, and eventually work his way up to saying “milk”
through these learned associations and shaping processes. It’s good to be understood, right?
But as usual, not everyone was on board with Skinner. In particular, legendary American
linguist Noam Chomsky argued that a kid like Bruno would never reach his full, complex,
sonnet-writing potential if his learning was dependent on conditioning alone.
Chomsky instead proposed the idea of innate learning and ubiquitous grammatical categories,
pointing out that while the world’s thousands of languages may sound wildly diverse, they’re
actually very similar, sharing some basic elements. He called this Universal Grammar.
Chomsky’s Universal Grammar posited that all human languages contain nouns, verbs,
and adjectives, and humans are born with an innate ability to acquire language, and even
a genetic predisposition to learn grammatical rules. Rather than being linguistic blank slates,
Chomsky suggested we’re hard-wired for it from day one.
In the end though, we’re still not sure how we acquire language. However, developmental
research and studies of other species have given us a sense that at least some of it
is innate, while the role of learning and exposure is also important. So if it’s true that all humans have some
innate capacity for language, where in the brain is it sitting?
We’ve talked a lot about how function is localized in the brain, and that’s definitely
true for some aspects of language. But while speaking, reading, writing and even singing
all fall under the language umbrella, their “locations” in the brain are a little
more complicated. Consider aphasia, a neurological impairment
of language. People can experience lots of different kinds of aphasia depending on whether
they’ve suffered an injury, or stroke, or a tumor, or dementia. So, maybe they can speak
but not read, or sing but barely speak, or write but not read.
The region of the brain known as Broca’s area in the left frontal lobe is involved
with the production of speech. If I suffered a trauma to this area, I might still comprehend
speech, but struggle to speak – although I might still be able to sing, because that’s
conducted elsewhere in the brain. On the other hand, if that falling coconut
struck another region, called the Wernicke’s area, a region in the left temporal lobe involved
in the expression and comprehension of language, I’d still be able to speak, but my language
wouldn’t make any sense. So you might find me saying something like, “It was too pizza,
but I called purple brother on the television.” Aphasia and other brain injuries remind us
how thinking and language are both separate and intricately entwined. For instance, it’s
hard to say if “non-verbal” ideas come to us first, and then we think of the words
to name them, or if instead our thoughts are born in language, or if we’d even be unable
to even think without it. And because language often helps to frame
your ideas, your thinking might actually be influenced by which language you’re using. So what are implications of this if we expand
the definition of language to include other species? How might Kanzi’s ability to communicate
that he wants a marshmallow affect his thinking, and how might that thinking influence his
language progression, and his identity? If only I had the words to describe how fascinating
it all is. If you understood the language I was using
today, you learned how languages are built from phonemes, morphemes, and grammar, and
when children acquire receptive and productive language, and pass through the babbling, one-word
and two-word phases of development. You also learned some theories on how we acquire language,
what brain areas are involved, and how thinking and language are connected. Thanks for watching, especially to all of
our Subbable subscribers. If you’d like to sponsor an episode of Crash Course, or
even be animated into an upcoming episode, just go to subbable.com/crashcourse. This episode was written by Kathleen Yale,
edited by Blake de Pastino, and our consultant is Dr. Ranjit Bhagwat. Our director and editor
is Nicholas Jenkins, the script supervisor is Michael Aranda, who’s also our sound
designer, and the graphics team is Thought Café.