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In the 1980s, a bonobo named Kanzi

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learned to communicate with humans[br]to an unprecedented extent—

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not through speech or gestures,

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

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

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answer verbal questions [br]from human researchers,

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and refer to objects [br]that weren’t physically present.

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Kanzi’s exploits ignited immediate [br]controversy over one question:

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had Kanzi learned language?

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What we call language is something [br]more specific than communication.

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Language is about sharing [br]what’s in our minds:

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stories, opinions, questions, [br]the past or future,

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imagined times or places, ideas.

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It is fundamentally open-ended,

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

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Many researchers are convinced [br]that only humans have language,

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

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

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for a limited total number of messages

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that aren’t combined [br]into more complex ideas.

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For example, a monkey species [br]might have a specific warning call

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that corresponds to a particular predator,[br]like a snake—

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

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

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of human language.

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

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and it's possible this definition [br]of language,

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

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But as far as we know, [br]only humans have language.

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And while humans speak [br]around 7,000 distinct languages,

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any child can learn any language,

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indicating that the biological machinery[br]underlying language

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is common to all of us.

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So what does language mean for humanity?

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

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

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Chimps and bonobos [br]are our closest living relatives,

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but the lineage leading to humans [br]split from the other great apes

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more than four million years ago.

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

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

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

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it may have started as gesture [br]rather than speech.

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

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than they vocalize.

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Language may have begun to take shape[br]during the Pleistocene,

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

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

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

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There may have been a transition [br]from gestural communication

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to gestural language—

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from pointing to objects [br]and pantomiming actions—

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to more efficient, abstract signing.

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

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setting the stage for a transition [br]to spoken language.

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That transition would have [br]likely come later, though.

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Articulate speech depends [br]on a vocal tract of a particular shape.

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Even our closest ancestors, [br]the Neanderthals and Denisovans,

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had vocal tracts that were not optimal,

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though they likely had [br]some vocal capacity,

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and possibly even language.

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Only in humans is the vocal tract optimal.

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

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So it may have been [br]the emergence of speech,

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

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

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that it’s difficult to untangle[br]its biological origins.

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Some of the biggest mysteries remain:

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to what extent did language [br]as a capacity shape humanity,

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and to what extent did humanity [br]shape language?

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

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or our ability to share them?