Can gorillas communicate verbally? When Koko wants a clean glass, she breathes heavily on the crystal before wiping it off. And, rather playfully, she sometimes makes a series of unintelligible grunts while pretending to talk on a toy phone. Plainly put, it might be that all apes are in fact closer to speaking than we give them credit for.

However, the one breakthrough Koko never had involved controlling her vocal communication, as it was thought apes only made vocal noises reflexively, thanks to previous research.

Marcus Perlman says that Koko stands on the fine line between gorillas and humans, since her behaviors did not come from being raised in the wild, but from her absorption into a human world: “Koko doesn’t produce a pretty, periodic sound when she performs these behaviors, like we do when we speak, but she can control her larynx enough to produce a controlled grunting sound”. Ever since, says Perlman, scientists had accepted “that apes are not able to voluntarily control their vocalizations or even their breathing” – until now.

However, after Perlman and Clark examined the videos of Koko, they realized she was performing nine different-and voluntary-behaviors that required control over her vocalizations and breathing. In the video below, you can watch Koko play a recorder.

Researchers have long assumed that speaking is an impossibility for apes because they can’t properly control their vocalizations or their breathing. Documented gorilla vocalizations were limited to a set of calls related to relaying information about the environment (such as the presence of food or predators) or the apes’ emotional states.

Koko can also cough on command – not particularly groundbreaking human behavior, but impressive for a gorilla because it requires her to close off her larynx.

The findings have some fascinating implications for our understanding of the evolution of language. But the whole picture may be more complicated than that, and it’s distinctly possible that the seeds of spoken language go much further back than we’ve thought.

This suggested that some of the evolutionary groundwork for the human ability to speak was in place at least by the time of our last common ancestor with gorillas, estimated to be around 10 million years ago. These were learned behaviors and not part of the typical gorilla repertoire. Hence, they lack the ability to speak.