CNN —
What’s in a swear? The world’s filthiest words typically refer to something vulgar or taboo, for one.
But there’s something else swears across the world’s languages have in common. They’re all missing the more melodic consonant sounds you’re more likely to hear in a lullaby than in a colorful reaction to a stubbed toe.
Swear words lack the consonant sounds l, r, w and y across several languages – including Chinese, English and Spanish, according to a new study from researchers at Royal Holloway, University of London. The team set out to find “phonetic patterns” in profanity in several disparate dialects.
“Swearing – like religion, or music – is a ubiquitous phenomenon across cultures,” study co-author and psychology professor Ryan McKay told CNN. “Our work suggests that it’s not just the semantic content of words that gives them their potency, but that the sounds in these words may also play a role.”
Growing up in Western Australia, McKay was exposed to “quite colorful language,” he said. He noticed that swear words in English contain “a preponderance of plosive” sounds – p, t and k – in which the mouth completely closes after forming the sound. (Try it out with your favorite English-language curse word and notice how it feels.)
McKay said he wondered whether the plosive sounds “allow an especially emphatic expression of emotion.”
He sought the expertise of psychology department lecturer Shiri Lev-Ari, an expert in “sound symbolism,” in which words have sounds that suit their meanings. Think words like “glass” or “glisten,” whose sounds suggest something shiny and smooth, with the definitions to match.
McKay said the pair expected to find evidence of the “plosive” sounds across languages or a “universal phonetic template for swearing,” with sounds dictating the evolution of swear words in different tongues.
What they found, though, was that in several languages, swear words are missing the l, r, w and y sounds. Those four consonant sounds are known as approximants – sounds that only slightly restrict the vocal tract but otherwise allow air to flow freely when they’re uttered.
For their first study, they recruited speakers of Hebrew, Hindi, Hungarian, Korean and Russian and asked them to list their languages’ most vulgar and filthy words. They analyzed those words and compared them to “control words” – that is, neutral words that aren’t considered swears in each language – and broke down their consonant sounds.
The only discernible pattern they could find among the swear words were the missing sounds throughout: the approximants l, r, w and y.
They enlisted Arabic, Chinese, Finnish, French, German and Spanish speakers for their second study. The subjects were presented with two words in a language they didn’t speak and asked to pick out which words they thought was the swear. (The researchers made up many of the words for this part of the study, based on existing words in different languages.)
The participants were “significantly less likely” to select the words with approximants when asked to identify swear words, McKay and Lev-Ari wrote.
Curse words across languages are often missing those approximant sounds and therefore are less sonorous when they’re spoken. A profane example lies in the f-word, which in English ends abruptly, restricting air flow when the “k” sound is made.
Curiously, when people are trying to clean up their language or replacing swear words with similar clean ones like “frick,” or “darn,” they reintroduce those missing consonant sounds, McKay and Lev-Ari found.
Those almost-but-not-quite-curses are called “minced oaths,” words that sound similar to, but still notably different from, swear words.
“We found that people tend to introduce these sounds into swear words when seeking to soften them for polite company,” McKay said.
As for why the approximants are unsuitable for curse words, McKay said he can only speculate. He noted, though, that humans and other animals make “harsh, abrasive sounds when distressed” and smooth sounds when they’re safe and content.
“It may be that people associate sounds like l, r, w and y with calm, and so perceive them as unsuitable for expressing anguish or frustration,” he said.
Swear words are powerful, Lev-Ari and McKay wrote: They’re used for emphasis, for shock value, even for pain tolerance. It makes sense that speakers of swears would avoid more fluid consonant sounds, which lend themselves better to more melodic words than curt curses do.