Evolution’s great mystery: Language - Michael Corballis

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 its 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,

2-3 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?

Did the vast number of scenarios we can
envisage

come before our ability to share them,
or did they evolve in concert?