What would you say if you suddenly stubbed your toe on a doorframe? Depending on how much it hurt, you might cry out in pain, unleash a stream of expletives—or utter a very specific exclamation, such as “ouch” or “ow.”
Most languages have a word that that serves as interjection for expressing pain. In Mandarin, it’s “ai-yo.” In French, it’s “aïe.” And in several Indigenous Australian languages, it’s “yakayi.” All have sound elements that seem quite similar—and that’s no coincidence, according to a new study in the Journal of the Acoustical Society of America. Researchers found pain interjections are more likely to contain the vowel sound “ah” (written as [a] in the International Phonetic Alphabet, or IPA) and vowel combinations that use it, such as “ow” and “ai.” These findings may point back to the origins of human language itself.
“Across every country, you see this overrepresentation of ‘[a]’” in pain interjections, says the study’s senior author Katarzyna Pisanski, who studies vocal communication at France’s National Center for Scientific Research (CNRS). “It was a really strong, robust effect.” Pisanski and her colleagues also found that [a] dominates the nonlinguistic, often involuntary cries of pain, called vocalizations, that people utter around the world. This suggests that words like “ouch” may have been shaped by the more primal sounds of pain that humans evolved to make—possibly well before language or speech developed.
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Maïa Ponsonnet, the study’s lead author, first noticed the similarity between “yakayi” and the French “aïe” while studying Indigenous languages of Australia. Obviously, “this is a very naive observation,” says Ponsonnet, a linguist who also works at CNRS. “You shouldn’t draw any inference from observations of just two languages.” So Ponsonnet and her colleagues scoured dictionaries and databases of 131 world languages for interjections that express pain and two other basic emotions, disgust and joy. The sample included dozens of language families from Asia, Australia, Latin America, Africa and Europe.
The researchers found striking statistical similarities in pain interjections across languages. In fact, these interjections resembled one another across languages more than they resembled other words of the same language. This effect—which did not hold true for interjections expressing joy or disgust—was driven by one category of vowels in particular: [a]-like ones that often combine with others to create sounds such as “ai” and “ow.”
“It doesn’t often happen that a hypothesis … is tested on such a large scale and comes out so clearly,” says Mark Dingemanse, a linguist at Radboud University in the Netherlands, who also studies interjections.
The pattern suggests that the words we humans use for pain are not as arbitrary as many other words. Instead they have likely been shaped by some common factor. Could those similarities come from the primal, nonlinguistic sounds that seem to automatically spring from us humans when we get hurt? Research on this is scant, so Ponsonnet joined forces with Pisanski, who studies the evolution of vocal communication in mammals, to conduct another experiment. The researchers recruited 166 speakers of English, Japanese, Spanish, Turkish or Mandarin to produce the sounds they would make if they were experiencing pain, disgust or joy.
This time the team found that—for each emotion—vocalizations contained similar vowel sounds across those five languages. For disgust, the most common vowel was [ə] (pronounced like “uh”); for joy, it was [i] (pronounced like “ee”); and for pain, it was the now familiar [a].
The fact that [a] was overrepresented in both primal vocalizations and interjections for pain suggests that these two types of utterance may be related, Pisanski says. It’s possible that words like “ouch” and “yakayi” have been shaped by the involuntary sounds we evolved to make in order to signal pain or distress to one another.
For disgust and joy, the results tell a different story. While the vocalizations for these emotions are similar across the world, their interjections were far more diverse—perhaps because these feelings carry more cultural dimensions than pain, Pisanski suggests. “Pain is pain, I think, no matter where you’re from,” she says. “It’s a biological experience.”
Our shared biology has impacts across many aspects of language. Researchers are continually discovering cases of symbolism, or sound iconicity, in which the intrinsic nature of a word has some connection to its meaning. These cases run counter to decades of linguistic theory, which had regarded language as fundamentally arbitrary (meaning, for example, that there was nothing in the structure or sounds in the word “bird” that would intrinsically make someone think of an actual bird).
Yet iconicity often does show up all over human language. Signed languages, long overlooked by many linguists, employ a lot of symbolism: in American Sign Language, “bird” is formed by using a finger and thumb to mime a bird’s beak opening and closing. And in spoken languages, the term onomatopoeia refers to words that imitate sounds directly, such as “bang” or “splat.” Many types of birds, such as the cuckoo and chickadee, have been given names that echo their calls.
But these connections between form and meaning can be so abstract that they’re all but invisible until revealed by researchers. For example, there’s the classic “bouba-kiki” effect, in which people around the world are more likely to associate the nonsense word “bouba” with a rounded shape and “kiki” with a spiked one.
“This is [what’s] beautiful about sound iconicity and symbolism—because somehow we all have a feeling about this,” says Aleksandra Ćwiek, a linguist at the Leibniz Center for General Linguistics in Germany. “It’s amazing to see that people kind of agree on them.” In a paper published last week, also in the Journal of the Acoustical Society of America, Ćwiek and her colleagues showed that people associate the trilled “R” sound with roughness and the “L” sound with smoothness.
“Finding out when unrelated languages do things in similar ways brings home our common humanity,” says Dingemanse, who in 2013 found that “Huh?” and similar words in other languages are universal in conversation. “No matter how much languages differ—and that is also fascinating—they also unite us.”
