In the 1980s, a bonobo named Kanzi

learned to communicate with humans
to an unprecedented extent—

not through speech or gestures,

but using a keyboard of abstract symbols
representing objects and actions.

By pointing to several of these in order,
he created sequences to make requests,

answer verbal questions 
from human researchers,

and refer to objects 
that weren’t physically present.

Kanzi’s exploits ignited immediate 
controversy over one question:

had Kanzi learned language?

What we call language is something 
more specific than communication.

Language is about sharing 
what’s in our minds:

stories, opinions, questions, 
the past or future,

imagined times or places, ideas.

It is fundamentally open-ended,

and can be used to say 
an unlimited number of things.

Many researchers are convinced 
that only humans have language,

that the calls and gestures other species
use to communicate are not language.

Each of these calls and gestures generally
corresponds to a specific message,

for a limited total number of messages

that aren’t combined 
into more complex ideas.

For example, a monkey species 
might have a specific warning call

that corresponds to a particular predator,
like a snake—

but with language, there are countless 
ways to say “watch out for the snake.”

So far no animal communication seems 
to have the open-endedness

of human language.

We don’t know for sure what’s going
on in animals’ heads,

and it's possible this definition 
of language,

or our ways of measuring it,
don’t apply to them.

But as far as we know, 
only humans have language.

And while humans speak 
around 7,000 distinct languages,

any child can learn any language,

indicating that the biological machinery
underlying language

is common to all of us.

So what does language mean for humanity?

What does it allow us to do, 
and how did we come to have it?

Exactly when we acquired this capacity
is still an open question.

Chimps and bonobos 
are our closest living relatives,

but the lineage leading to humans 
split from the other great apes

more than four million years ago.

In between, there were many species—
all of them now extinct,

which makes it very difficult to know
if they had language or anything like it.

Great apes give one potential clue 
to the origins of language, though:

it may have started as gesture 
rather than speech.

Great apes gesture to each other 
in the wild much more freely

than they vocalize.

Language may have begun to take shape
during the Pleistocene,

2 to 3 million years ago, 
with the emergence of the genus Homo

that eventually gave rise 
to our own species, homo sapiens.

Brain size tripled, and bipedalism 
freed the hands for communication.

There may have been a transition 
from gestural communication

to gestural language—

from pointing to objects 
and pantomiming actions—

to more efficient, abstract signing.

The abstraction of gestural communication
would have removed the need for visuals,

setting the stage for a transition 
to spoken language.

That transition would have 
likely come later, though.

Articulate speech depends 
on a vocal tract of a particular shape.

Even our closest ancestors, 
the Neanderthals and Denisovans,

had vocal tracts that were not optimal,

though they likely had 
some vocal capacity,

and possibly even language.

Only in humans is the vocal tract optimal.

Spoken words free the hands for activities
such as tool use and transport.

So it may have been 
the emergence of speech,

not of language itself, that led 
to the dominance of our species.

Language is so intimately tied to complex
thought, perception, and motor functions

that it’s difficult to untangle
its biological origins.

Some of the biggest mysteries remain:

to what extent did language 
as a capacity shape humanity,

and to what extent did humanity 
shape language?

What came first, the vast number 
of possible scenarios we can envisage,

or our ability to share them?