April Observations

A few weeks ago, I came across a news headline stating that a bonobo named Kanzi had passed away. My first thought was immediately: what is a bonobo, and why is this bonobo the subject of so many news articles? After researching, I discovered that a bonobo is in fact a type of ape found solely in the Democratic Republic of the Congo, and that this animal can actually teach us quite a lot about language. 

Specifically, Kanzi is a bonobo who was born in captivity and learnt to use a Yerkish keyboard made up of lexigrams that represent different objects. Over time, not only did he develop an ability to press the various symbols, but he actually did so in a way that indicated that he understood their meanings. For example, he would press a key for a certain food and then go collect that food from a refrigerator. In fact, the way that he became familiar with the symbols through pure exposure as opposed to explicit training is extremely similar to how human children learn language. Beyond this, Kanzi was able to creatively combine his lexigrams to form new meanings. Once, when he tried kale, he called it “slow lettuce” since he had to chew it more slowly than regular lettuce. While mastering Yerksih, Kanzi simultaneously developed a strong understanding of spoken English too! In a study, he responded correctly to 74% of spoken instructions, while a 2-year-old named Alia only responded correctly to 65% of them. 

There is still a lot of debate on whether Kanzi was truly acquiring language or whether he was making use of other non-linguistic cognitive abilities like memory. What we can take out of his language-learning journey, though, is that just because bonobos do not engage in symbolic communication in the wild, it does not mean that they do not have the cognitive capacity to do so. During the 44 years of his life, Kanzi had a major impact on the field of linguistics and he will be remembered for the way his actions challenged existing beliefs about language.

But, fascinating linguistic discoveries are not limited to Kanzi! It was recently found that all bonobos may be able to combine words in a way that was previously thought to be unique to humans. In linguistics, compositionality refers to the meaning of a phrase being determined by the meaning of its individual words and their relationship to each other. In “trivial compositionality,” each unit adds independent meaning to the phrase. For example, when someone uses the phrase “blonde dancer,” the speaker is referring to a blonde person who is also a dancer. However, when someone uses the phrase “bad dancer,” the speaker is referring to a person who is bad at dancing, as opposed to a bad person who also dances. This case is called “non-trivial compositionality” and includes a word in the phrase that is modifying the other. Researchers previously believed that “non-trivial compositionality” was unique to humans. However, a new study based on 700 recorder vocalization suggests that bonobos may use both types of compositionality in their oral communication, even though the nontrivial compositionality detected in bonobos is less complex than the one in human language.

Overall, while we still have so much to learn about bonobos, they are clearly really unique and seem to have a relationship to language that is different from all other animals. 

Credit: Works and Days

Works Cited

Bassi, Margherita. “There Might Be Something Human in the Way Bonobos Communicate—Their Calls Share a Key Trait with Our Language, Study Suggests.” Smithsonian Magazine, 4 Apr. 2025, www.smithsonianmag.com/smart-news/there-might-be-something-human-in-the-way-bonobos-communicate-their-calls-share-a-key-trait-with-our-language-study-suggests-180986370/. Accessed 30 Apr. 2025.

Berdugo, Sophie. “Bonobos Use a Kind of Syntax Once Thought to Be Unique to Humans.” New Scientist, 3 Apr. 2025, www.newscientist.com/article/2474993-bonobos-use-a-kind-of-syntax-once-thought-to-be-unique-to-humans/. Accessed 30 Apr. 2025.

Hieber, Daniel W. “Did Kanzi the Bonobo Understand Language?” Linguistic Discovery, 31 Mar. 2025, linguisticdiscovery.com/posts/kanzi/. Accessed 30 Apr. 2025.

Kluger, Jeffrey. “Inside the Minds of Animals.” TIME, 5 Aug. 2010, time.com/archive/6597423/inside-the-minds-of-animals/. Accessed 30 Apr. 2025.

Wong, Kate. “Kanzi the Bonobo, Who Learned Language and Made Stone Tools, Dies at Age 44.” Scientific American, 29 Mar. 2025, www.scientificamerican.com/article/kanzi-the-bonobo-who-learned-language-and-made-stone-tools-dies-at-age-44/. Accessed 30 Apr. 2025.