Could a chimpanzee ever learn to speak, or are we uniquely wired for language?

Nature · Published 3 October 2026 Swipe more like this →

In short: In 1973, psychologist Herbert Terrace launched a bold experiment to teach an infant chimpanzee, Nim Chimpsky, American Sign Language. While Nim learned 128 signs, the project ultimately revealed a profound truth about the divide between human and ape cognition, challenging our understanding of how language truly evolves.

Project Nim was designed to challenge the theories of linguist Noam Chomsky, who argued that humans are biologically predisposed to language. Terrace, a Columbia University professor, placed an infant chimpanzee with a family to be raised in a human-like environment. Over several years, Nim was trained by a rotating group of roughly 60 caregivers, including students and volunteers, to communicate using American Sign Language. The chimp successfully learned 128 signs and could produce sequences of gestures, seemingly mirroring human linguistic development.

However, Terrace eventually concluded that Nim’s performance was not true language. Upon reviewing video footage, he realized the chimp was not spontaneously initiating conversation or forming complex sentences. Instead, Nim was mimicking his teachers, who inadvertently prompted him by signing just before he did. The chimp’s primary motivation was reinforcement; he signed to obtain food, drink, or physical affection. Because Nim lacked the ability to understand that things have names—a milestone human infants reach by 12 months—he could not master the foundational requirements of language.

The experiment also faced significant ethical and methodological criticism. The project suffered from high staff turnover, inconsistent training methods, and the use of harsh disciplinary tactics, such as confinement and cattle prods. Furthermore, many caregivers were not proficient in American Sign Language, teaching Nim a simplified pidgin version rather than the actual language. These factors led some to argue that the study was less about linguistics and more a case study in trauma.

Ultimately, the project helped clarify why humans are unique. Terrace suggests that human language relies on the ability to name objects and recombine words to create new meanings, skills that apes do not possess. This divergence is rooted in early development; human infants are born less developed than other primates, requiring prolonged cradling that fosters eye contact and shared attention. This shared focus on objects is the essential first step in acquiring language, a mechanism that remains absent in the chimpanzee mind.

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