Language in great apes
What Washoe the Chimpanzee Actually Proved About Language
A chimpanzee once signed 'water bird' when she saw a swan — and that single moment split the scientific world in two.
The Idea
In the late 1960s, a chimpanzee named Washoe became the first non-human animal to learn American Sign Language, and she did something nobody had explicitly taught her: she started combining signs in novel ways. When she wanted you to hurry, she'd sign 'come' and 'open' together. She taught signs to her adopted son without human prompting. This looked, thrillingly, like the edge of language. But here is where the story gets genuinely complicated. Language, in the technical sense linguists care about, isn't just symbol use — it's recursive, generative structure. You can embed a sentence inside a sentence inside a sentence, and a native speaker will parse it effortlessly. No ape has convincingly demonstrated that capacity. What Washoe and the chimpanzees who followed her — Nim Chimpsky, Kanzi the bonobo, Koko the gorilla — showed us was something both more modest and more interesting: the symbolic threshold is not as bright a line as we assumed. The real revelation isn't that apes 'have language' or definitively don't. It's that the components we thought were bundled together — symbol use, intentional communication, reference, even a rudimentary grammar — can exist independently of each other. Apes clearly possess some of these. The question of which ones, and to what degree, has quietly redrawn the map of what we consider distinctly human.
In the World
Kanzi's story is the one that tends to stop people cold. Born in 1980 at the Language Research Center in Georgia, Kanzi is a bonobo who learned to communicate not through signing but via a lexigram board — a panel of abstract symbols, each representing a word. His mother was the one being trained; Kanzi just watched. Then one day researchers realised he had absorbed the system on his own, without a single formal lesson. What made Kanzi genuinely startling was his apparent grasp of spoken English. In controlled tests, he responded correctly to novel sentences he had never heard before — sentences like 'put the ball on the pine needles' or 'go get the tomato that's in the microwave.' He wasn't pattern-matching from training; he was parsing unfamiliar syntax in real time. His accuracy hovered around 70 to 80 percent, comparable to a two-and-a-half-year-old human child who was tested alongside him. Psychologist Herbert Terrace, who had run the Nim Chimpsky project, remained deeply sceptical. He argued that most ape signing was unconscious imitation and cue-following — that trainers were inadvertently signalling the 'right' answers, an echo of the famous case of Clever Hans, the horse who seemed to do arithmetic but was actually reading micro-expressions. The debate never fully resolved. Kanzi grew old at a sanctuary in Iowa. He still uses his lexigram board.
Why It Matters
What you take away from the ape language debate depends on what question you think is worth asking. If the question is 'can apes talk?' the answer is clearly no, and probably always was. But if the question is 'what is language built from, and how did it emerge?' then apes become enormously useful mirrors. They help us see that communication, reference, symbol use, and syntax are not a single thing that either exists or doesn't — they're a layered architecture, and evolution appears to have handed out the components unevenly across species. That should change how you think about the origins of your own language. It didn't arrive fully formed. It assembled itself, piece by piece, from capacities that were already there for other purposes. There's also a quieter implication: if a bonobo can acquire symbolic communication incidentally, by observation rather than instruction, that suggests the cognitive machinery for symbol use is far older and more widespread than the language faculty itself. Which makes you wonder what else is being quietly understood, in enclosures and forests, by minds we haven't thought to ask.
A Question to Ponder
If an animal can learn symbols, understand novel sentences, and even teach others — but lacks the recursive grammar that defines human language — where exactly does the line between 'communication' and 'language' fall, and does that line matter as much as we thought?
Get a new one of these every morning.
Start learning with Thinkable