As anyone who has tried to blag a vocab test will know, words really don’t have any logic to them. You can’t just “work out” what the German word for “fridge” is. That’s because, of course, words are arbitrary. Cat (or katze or chat) only means “cat” because at some stage people came to agree that it did. Words may share roots and flit across language barriers, but because there’s such a vast number of sounds a human can make, it’s very unlikely that we’d all spontaneously come up with the same word for the same thing.

Except that, apparently, we have. That word is “huh”. According to a recent study it seems to be pretty universal. The scientists (in what sounds like an excellent idea for a research trip), recorded bits of informal language from 5 continents, and of the 31 dialects they compiled, all had this same word in common.

My first thought in reading their findings was “hmmm”. Is “huh” even a word? It seems more like an instinctive utterance - the kind of sound we make when confused. Noises of surprise or anger might be the same everywhere, but that’s because they are not really part of a language. They’re just noises.

But the researchers do a fairly good job of arguing that “huh” is, in fact, a word. It’s not involuntary, and it follows the rules of a given language: if questions are posed with rising intonation, “huh” rises too, and vice versa (it fell in two of the dialects). It is also possible for children and language learners to get “huh” wrong by using it out of context. You can’t get noises of astonishment wrong.

So why is “huh” everywhere? Here’s where the research gets interesting. “Huh”, the scientists suggest, is the only word that can do that particular job. This means you could, technically, work the word out in a vocab test. And if children were really thorough inventors of made up languages, they’d have to include “huh”.

It happens that at certain points in a conversation we need a word that can do a large number of things all at once. It must: 1) say there is a problem, 2) signal that the problem has to do with a lack of knowledge, and 3) ask for a response, without being sure what that response might be. But there is also pressure on the word to be as short as possible: it is a correction signal, so it should not disturb the rhythms of the language too much. And so we got “huh”: the ultimate low effort word (to make it you only need a tiny constriction of the vocal tract at its narrowest point), but capable of expressing as much bafflement as you can put into it.

You might say that environmental forces squeezed this word into shape. We see this happen in biology - sharks and dolphins, under the same constraints, independently developed similar body shapes - but rarely in language. In fact, this is the first clear case of such powers at work.

But it strikes me there is a new wave of strong and identical pressures on words across the world. As dialects are squeezed into 140 characters, and thousands struggle to come up with the perfect tweet of the moment, (instantly rewarding those who do) there is language mutation like no other. And across cultures we all tweet the same way - Twitter’s mood swings are the one of the most predictable phenomenons out there.

Thousands of years of language use produced a single universal word. My guess is the next one will emerge on Twitter.