Vocal Learners and Evolution


In 2010, an orangutan called Tilda at Cologne Zoo in Germany was filmed making a series of deep-throated garbled sounds similar to human speech. The video roamed the internet at the time; however, Tilda was not the first animal to mimic human speech. Other species make speech-like sounds, including whales, elephants, not to mention parrots; but, how do they make these human-like sounds?

For the orangutan, the answer lies in the complex musculature of its vocal tract and its thick and flexible tongue, which enable it to produce these speech-like sounds more easily. Other animals could mimic human speech; yet, using different methods. Whales, for example, could mimic human-like sounds by over-inflating their nasal cavities; elephants, on the other hand, put the tip of their trunks into their mouths to modulate their vocal tract.

You may think that, to talk, you need to have certain physiological abilities; but think of musical instruments. You will notice that some instruments you cannot do much with when their vocal tract is short, compared to longer ones, which are more versatile. Similarly, the human larynx is much longer than in other animals; so, why do some animals have talking abilities, while others do not?

What is common in these different mimicry species is that they are vocal learners; unlike other animals that produce only the calls they are born with and are unable to imitate new sounds. Vocal learners hear sounds, try to imitate them, and then produce them; yet, this minority of mimicry animals does not understand the meaning of these sounds, and as we say, are simply “parroting” them.

Accordingly, we may assume that humans are the best vocal learners. Humans have the ability to learn and form countless words, carrying different thoughts, but when did our speech and language evolve?

Our native languages, also known as natural languages, have evolved into their current form over centuries. Most scientists estimate that language first appeared among Homo sapiens 30,000–100,000 years ago. Unfortunately, where language began to rise and the secret of its evolution are still unknown; hence, many theories have popped up. One common theory assumes that language was the main reason behind the survival of human beings, where language was created to help humans communicate in order to hunt, farm, and defend themselves against their harsh environment.

Another competing theory posed by linguist Noam Chomsky and evolutionary biologist Stephen Jay Gould states that language was needed for social interaction; as part of the evolutionary processes, it has evolved. In their theory, they tackled Darwin’s preadaptation process, also known as exaptation, which discusses how species use their features for a purpose other than that it was originally made for. A classic example for exaptation as argued by some evolutionary biologists is the original function of birds’ feathers to shelter them from cold weather; they were later used for flying.

Chomsky and Gould hypothesize that, as the physical structure of the brain evolved, language may have evolved too; as humans started to construct different tools, there was a need to name each of them. This falls in line with the theory stating that our cognitive functions have increased as our brains were enlarging.

What is clear is that language is a human invention that developed as the need for more complexity increased. Our vocal mimicry was the ground of our language, which has allowed us to produce and reproduce a massive number of sounds. As a result, different forms of languages evolved; today we can, thus, find around 7,000 different languages spoken around the world.

We may conclude that, as stated by cognitive psychologist Steven Pinker: “This triad—language, social cooperation, and technological know-how—is what makes humans unusual. They probably evolved in tandem, each of them multiplying the value of the other two.”

Given the above, we may notice that many of the mechanisms involved, including the ability to control produced sounds, are basic and owned by many animals. Yet, only a tiny minority of animals was able to mimic the sounds of human speech and talk as humans do. If we think about the other majority of less capable animals that cannot mimic human-like sounds—and are still as fascinating as their peers—we can get a picture of how our linguistic abilities have evolved over the centuries.

*The article was published in SCIplanetLife Scences (Summer 2017) Issue.


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