Linguistic relativity can tell us about our perceptions of reality and the relationship between language and the way we think

Shortly after New Year's Eve, I sat in a Berlin airport, clutching my head. Around me a few other English EasyJetters waited, too, listening vaguely to the German voice coming over the loudspeaker. One of my bleary countrymen turned to another and said: "They sound like they're angry all the time, don't they? Speaking that language all day must do something to your brain."

The idea that the language you speak affects the way that you think sounds sort of obvious, one of those things you just assume. Speak French all day and you'll start thinking stylishly; speak Swedish all the time and start feeling really good about taxation. But what exactly is the relationship between what goes on in your head and the words you use? If, say, the Swedish didn't have a word for taxation (they do; it's beskattning), would they be able to conceive of it?

The principle of linguistic relativity is sometimes called the Sapir-Whorf hypothesis, or Whorfianism, after the linguist who made it famous, Benjamin Lee Whorf. Put simply, Whorf believed that language influences thought. In his 1940 essay, Science and Linguistics, influenced by Einsteinian physics, Whorf described his "new principle of relativity, which holds that all observers are not led by the same physical evidence to the same picture of the universe, unless their linguistic backgrounds are similar". His research appeared to show that speakers of different kinds of language were, as a result of those language differences, cognitively different from one another.

Whorf's hypothesis is one of those slices of 20th-century thought that embedded itself right away in the culture and then underwent an interesting trajectory, falling in and out of academic favour ever since. Ever heard the one about the people who have "no concept of time"? Inuit words for snow? All Whorf.

The time-less people were the Hopi, a Native American tribe who live in north-eastern Arizona. Whorf claimed that they didn't have any words for time – no direct translation for the noun time itself, no grammatical constructions indicating the past or future – and therefore could not conceive of it. They experienced reality in a fundamentally different way. The idea fascinated people: Whorf's work became popular "knowledge" but his credibility waned from the 60s onward. By the mid-80s, linguist Ekkehart Milotki had published two enormous books in two languages discrediting the "time-less Hopi" idea.

Now, pronouncements like those made by Whorf and my airport companions make me instantly suspicious. If Whorf's theory sounds a little odd to you, a little politically incorrect, perhaps you're an anxious liberal like me; if you subscribe to it wholesale (sometimes called the "strong" version of the hypothesis), you are consigning people from different speaking communities to totally different inner lives. Which sounds, well, racist. The idea that people who speak some particular language are incapable of certain kinds of thought is instinctively distasteful.

From the very first, scientific testing of Whorf's hypothesis seemed to prove him wrong. His idea that people cannot conceive of realities for which they have no words just doesn't make sense: how would we ever learn anything if that were true? We aren't born with words for everything that we understand.

Whorf was of a different time: his research came out of older traditions of thinking about language that have lost cultural traction. In the 18th and 19th centuries, writers such as Wilhelm von Humboldt believed that a culture's language encapsulated its identity, to the extent that different languages represented totally distinct worldviews. The late 19th century was the heyday for the idea that white culture was objectively the best, so you can see how this kind of theory really caught on.

However, if you see Whorf as both coming out of but also very different from that kind of thought, he turns out to be a real progressive. As part of a wider American group of thinkers (alongside anthropologist Franz Boas and others) in the early 20th century, Whorf opposed the idea of biological difference between peoples. In emphasising cultural relativism, however, they emphasised the conditioned differences between them. Nowadays, it is hard to read any emphasis on human difference without a little side-eye – and quite right, too.

As linguists such as Noam Chomsky began to redefine what it meant to study human language, linguistics generally swung from Whorf-style relativist positions to a more universalist approach, in which scholars tried to discover the general principles of language. Since the 80s, however, investigations into linguistic relativity have flourished anew, but in a much more careful, subtle way.

The study of the relationship between language and colour perception is one of the most striking areas of this research, not least because human beings are all of the same species and thus see with the same eyes – differences in defining colour must be something else. In 1969, Brent Berlin and Paul Kay published their book, Basic Color Terms: Their Universality and Evolution, in which they argued that there were rules for how all people label colours: there are 11 basic colour categories and if there are fewer, they are added in a particular order (black and white, then black, white, and red, then black, white, red, and green or yellow).

Research supporting a relativist view includes studies of the way in which the Namibian Himba people label colour according to only five categories. The categories would be difficult for you to understand fully or reconstruct, in all probability: both zuzu and buru contain shades of blue, for example. This splitting up of shades into groups seems to affect how long it takes for a Himba person to tell the difference between colours that might look very different to you but that are labelled the same for them. (You can read more about the Himba in this study.)

The universalist and relativist schools of thought are no longer so clearly split from or opposed to each other and, we can but hope, ideology permeates academic research less and less. My bias against the principle of linguistic relativity is personal, influenced by my other general beliefs about the world. Linguistics is a subtle field growing ever subtler and it never does any good to assume.

Linguistic relativity is a subject that people will always be interested in, because it strikes right at the way we process the world and communicate with each other. I see people all the time on the subway in New York reading Guy Deutscher's lively book, Through the Language Glass: Why the World Looks Different in Other Languages. If you are looking for a more in-depth introduction to this topic than a Guardian article can provide, start there. If you are those guys who sat by me in the airport on the second of January, however, you need to take a hint from the Himba – you're seeing things in black and white.