Swear words are a powerful function of human language—so powerful that we aren’t supposed to say them, at least not in polite company. The right expletives, unleashed at the right moment, can be used to cause hurt or offense. They facilitate the expression of intense emotions. They may even help us better tolerate pain, as anyone who has yelped a curse word after stubbing a toe knows.
But why are certain words considered so profane that we feel the need to bleep them on TV and scold our kids for using them? According to a colorful new study in Psychonomic Bulletin & Review, which analyzed swear words across multiple languages, the way curse words sound—or don’t sound—may make them offensive to the human ear.
At the heart of the study is a fundamental question in the field of linguistics: Is language arbitrary? An established convention holds that yes, the relationship between the sound of words and their meanings is typically random. But some experts have challenged this notion, positing that certain sounds are “intrinsically associated with certain meanings,” write study authors Shiri Lev-Ari and Ryan McKay from Royal Holloway, University of London. Across many languages, for example, the word for nose is likely to include the nasal sound “n.”
Research has also shown that English swear words have a higher proportion of p, t, and k sounds, which are known as plosives. But, Lev-Ari and McKay wondered, is this just a quirk of English?
Searching for patterns among the world’s naughtiest words, the researchers asked fluent speakers of five unrelated languages—Hebrew, Hindi, Hungarian, Korean, and Russian—to list at least five of the most vulgar words in their language, excluding racial slurs. The study’s authors did not find a higher incidence of plosives in these expletives. But they did observe that the words in their data set were less likely to include approximants—sounds that include l, r, w and y—than might be expected by chance. Words containing these sounds, the authors theorize, may be less “suitable” for causing offense.
The researchers next recruited 215 people to listen to pairs of words in an unfamiliar language and indicate which one was the swear word. Unbeknownst to the participants, all the word pairs were imaginary, created by the study authors to include one word with an approximant and one without. Participants were more likely to guess that the words without approximants were profanity.
In the final phase of their study, the researchers looked at minced oaths—variations of English swear words that are considered less offensive, like “darn” as an alternative to “damn.” Approximants appeared more frequently in minced oaths than in the swear words themselves, suggesting once again that l, r, w and y don’t have the prickly effect of other sounds
“It may be that approximants are sound-symbolically associated with calm and contentment,” Lev-Ari and McKay write, “and so are unsuitable for giving offense.” In any case, the researchers conclude, the absence of approximants in expletives suggests there is a universal pattern to swearing—and when it comes to words that would make your grandma blush, sounds like l, r, w and y just don’t pack the right damn punch.