A first-of-its-kind study looking at more than 6,000 languages has found that people from around the world tend to use the same sounds to signify common objects and ideas.
The findings suggest that humans speak a kind of 'universal language', perhaps influenced by biology, and go against a long-standing principle of modern linguistics – essentially, that there is no link between the sounds and the meaning of words.
"These sound symbolic patterns show up again and again across the world, independent of the geographical dispersal of humans and independent of language lineage," says cognitive psychologist Morten H. Christiansen from Cornell University.
"There does seem to be something about the human condition that leads to these patterns. We don't know what it is, but we know it's there."
Christiansen's international team – including physicists, linguists, and computer scientists – conducted a massive analysis of almost two-thirds (62 percent) of the languages in use around the globe today.
Their investigation focused on basic vocabulary in each of these tongues, looking at the words used to describe up to 100 of the most common concepts people everywhere address every day: "dog", "ear", "water", "tooth", "you", and so on.
They found a strong statistical relationship (74 sound–meaning associations) between the common concepts and the vocal sounds people make when referring to them.
In other words, despite the fact that foreign languages can sound totally confusing if you don't understand them, there are actually a lot of similarities if you look closely – at least for the most common words, such as pronouns, body parts, properties ("small", "full") and verbs.
For example, the word for "nose" often involves "neh" or "oo" sounds; the terms for "red" and "round" usually include an "r" sound.
"It doesn't mean all words have these sounds, but the relationship is much stronger than we'd expect by chance," says Christiansen, noting that words for body parts in particular showed an unexpectedly high association between sounds and meaning.
And the associations can be negative too, with the words we use to describe things in different languages showing a common tendency to avoid particular vocal sounds – such as the word for "you", which is unlikely to include sounds involving the letters u, o, p, t, d, q, s, r, and l.
As you may have noticed from that example, English doesn't always obey the rules, and was noted as an outlier in many cases.
It's not the first time scientists have observed a relationship between the sounds of words and their meanings across different languages. But nobody's ever conducted such a huge analysis and shown just how far these commonalities – what's called sound symbolism – actually extend.
The findings – published in Proceedings of the National Academy of Sciences – could make some pretty big waves in the scientific community.
A century ago, Swiss researcher Ferdinand de Saussure suggested that there was no relationship between the sounds we make and the meanings we intend, and the idea remains as one of the defining principles of modern linguistic theory.
"Most models for how words come into our lexicon are predicated on this assumption that the sound doesn't tell you anything about what it represents," cognitive psychologist Jaime Reilly from Temple University, who wasn't involved in the study, told Sarah Kaplan at The Washington Post.
"So the really neat thing about this paper is it sort of questions whether that arbitrariness assumption actually holds across all words," he added. "It's going to end up being a very important study."
But why do so many human languages demonstrate these ties to this hidden, universal language of sounds that informs the way we speak?
The researchers aren't themselves sure. They considered it could be the remnant of some form of "prehistoric protolanguage" that was once spoken by the earliest humans before the evolution of modern languages – but their own analysis suggests it's more likely that biology is somehow at play here.
"Perhaps these signals help to nudge kids into acquiring language," says Christiansen. "Likely it has something to do with the human mind or brain, our ways of interacting, or signals we use when we learn or process language. That's a key question for future research."