Linguistic anthropologists have observed that people all over the world perceive languages, and speakers of those different languages, as fundamentally different from one another. When people listen to others’ speech, they hear discrete categorical boundaries even when differences in speech exist along a continuum. Our minds, and not just our ears, perceive these differences: we think of language X as being fundamentally different from language Y. From there, it is not a big leap to think of groups of speakers as being essentially different from one another: speakers of X are fundamentally different from speakers of Y.

You might assume that people are unconsciously conflating language with culture. After all, if someone speaks French fluently, they most likely come from France, where they were raised immersed in French culture. If that’s the case, people’s attitudes toward language could simply be a proxy for their attitudes toward perceived cultural differences across groups. But research suggests that people’s intuitions and misperceptions about the social life of language run much deeper than this, and manifest themselves in some surprising ways.

Indeed, people essentialize language. Psychological essentialism is the notion that particular groups of people are different because of some real, meaningful underlying essence that is present deep in their nature, and often biological in origin. So if you think that French speakers are fundamentally different from English speakers because of something about their essential nature or the biology they were born with—rather than the situational or cultural variable of having lived and been exposed to French rather than English—you are using essentialist reasoning. This common but misleading mental habit shapes our thinking in many domains.

What’s more, as a reflection of this essentialist thinking, it’s not uncommon for people to think that when you learn a new language, you may instantly learn a new set of beliefs, ideas or customs. As Harvard literature professor Marc Shell writes, “Many people maintain that they cannot change their language without ipso facto also changing their gods and themselves.” Brandeis University anthropologist Janet McIntosh calls this “linguistic transfer”—the idea that by speaking a new language, you—perhaps suddenly and somewhat mystically—take on the psychic properties of people who speak that language. She has studied this in Kenya, where some people report that language defines their selves, their rights, their land and their religion—and they say that learning to speak a new language could risk changing any of these.

One place where this essentialist thinking can often lead us to societal trouble is when we assume that the language of certain members of a group is “pure”—that is, it has a unique characteristic essence—and that some people may be “less pure” group members than others, based on how they speak. In short, people may infer that you can’t be an authentic member of a group or a culture without speaking the relevant language in a certain way.

You don’t need to go that far from home to see linguistic essentialism in action. Soon after World War I, the supreme court of Nebraska upheld a law asserting that “Languages, other than the English language, may be taught as languages only after a pupil shall have attained and successfully passed the eighth grade.” The justices wrote that speaking a foreign language could “naturally inculcate in [children] the ideas and sentiments foreign to the best interests of this country.”) Fortunately, the state’s law was subsequently overturned by the U.S. Supreme Court in Meyer v. State of Nebraska (1923).

People feared teaching a child a foreign language, because it seemed the child’s mind might as a result take on anti-American ideas. In East Africa, the American Midwest or apparently anywhere in the world, the underlying assumption seems to prevail: what you know—and perhaps the way you feel or think—is somehow embedded in your language. Learning a new one could transfer a set of new ideas into your head.

To put it mildly, people have some funny beliefs about language imbuing speech with mystical powers that in fact having nothing to do with the way we talk. This peculiarity extends to our beliefs about how languages are acquired—and our assumptions about whether languages are learned through hearing people talk to us or by other, more “essentialist” means.

If you’ve read this far, you won’t be surprised to hear that humans have the biological faculty to learn and reproduce languages, and children learn languages that they hear in their environment. Yet sometimes people seem to think that the ability to speak a particular language, rather than a different one, is embedded in a person’s nature, rather than learned from exposure to it.

To illustrate the absurdity—and long history—of this notion, linguists often retell the ancient story of the Greek historian Herodotus, who in about the fifth century B.C. wrote about an ancient psycholinguistics experiment. Allegedly, the Egyptian king Psammetichus wanted to figure out which language was the true first language on earth, the one that most perfectly reflected the human soul: was it Phrygian or Egyptian? According to the story, he separated two babies from their mothers and sent them to be raised by herders. The babies’ physical needs were to be met, but no language was to be spoken in their presence. Lo and behold, as toddlers, they were overheard speaking their first words in Phrygian, the true language of humanity!

Presumably, the babies did not learn the Phrygian language on their own. Maybe the herders spoke Phrygian among themselves, didn’t follow instructions, and talked to the babies, exposing them to the language. Or maybe the story is made up. Whatever the case, Herodotus’s tale reflects our intuition that the ability to speak one language instead of another is somehow rooted in biology, and a child might inherit it.

In the real world, as we’ve seen, children are born with the remarkable ability to learn languages—but no child is born with the aptitude to speak any one in particular. Logically, speaking English rather than French, or Spanish rather than Japanese, could not possibly be codified in your DNA. It is rare to find an absolute truth in just about any field of study, but I will go out on a limb and say that if you are not exposed to French, there is about a zero percent chance that you will learn it.

But that doesn’t put the kibosh on the strange intuition that speaking one language over another is somehow written into the genetic code. As Steven Pinker writes in his seminal book The Language Instinct, which examines humans’ remarkable language learning abilities, this belief is widespread but utterly false:

“This folk myth is pervasive, like the claim of some French speakers that only those with Gallic blood can truly master the gender system, or the insistence of my Hebrew teacher that the assimilated Jewish students in his college classes innately outperformed their Gentile classmates. As far as the language instinct is concerned, the correlation between genes and languages is a coincidence. People store genes in their gonads and pass them to their children through their genitals; they store grammars in their brains and pass them to their children through their mouths.”

Now, you might not need to be convinced that language is passed, as Pinker says, from people’s mouths, not their gonads. However, I have observed that even enlightened modern adults, young and old alike, sometimes think of others as defined by and linked to their native tongue, or to the native tongue of their biological forbears.

A colleague of mine is a psychology professor at a large university. In a particular class, she spends a day teaching about language acquisition, typically mentioning research on international adoptions, such as studies of Korean children adopted by French families, who grow up to speak French (and not Korean). She says it does not happen frequently, but every so often, a student will express surprise that an ethnically Asian child could learn French so well. When asked to explain their thinking, they offer the opinion that someone who is ethnically Asian would have an easier time learning a “typically Asian” language; French was better suited to white children. In truth, any child can learn any language; it’s just a matter of being exposed to it. But some adults hold the mistaken belief that something about your genes specifies which language it would be easier for you to learn—even as a baby.

To give another example, a (white, Midwestern-accented) friend of mine recently told me the following story. Her cousin adopted twin African American girls, at age one and a half. The cousin had suffered from infertility for years and desperately wanted a baby; when the opportunity arose to have two at once, she was overjoyed. Fast-forward 11 years, and the girls are becoming adolescents. They are rebelling and finding their own footing, like adolescents everywhere. And their quest for self-definition has extended to their speech.

Recently, the twins’ mom shared, her daughters sounded different to her. As she struggled to articulate this idea, she mentioned to her cousin (my friend) that she thought they sounded Black. Trying to figure out why their speech had suddenly changed, she mused aloud. Perhaps their biological mom (whom she had never met) had spoken a dialect of African American English. Maybe the twins were exposed to this dialect early in life and it stuck, somehow. Or maybe it was transferred in utero, or inherited in their DNA? Could that be why, all of a sudden, it sounded like they were speaking differently?

Of course, the answer is that no dialect of English had been handed down in the girls’ DNA. This is simply impossible. Dialects (and all languages) are learned via linguistic exposure. For the twins, like for anyone, their changing speech must reflect changing conversations and social role models in their environment. Yet, you can see in the mom’s thinking linguistic essentialism, clear as day.

Studies of children provide some insight into adults’ puzzling intuitions about language and where those languages may come from. Some fascinating evidence suggests that children start out with a pretty naive theory, thinking that learning a specific language (such as French instead of English) comes from biology, not environment. Some adults may hold on to this childhood intuition, even after experience should have debunked it.

In one experiment that nicely demonstrated children’s thinking, Susan Gelman and Lawrence Hirschfeld gave Michigan preschoolers a “switched at birth” task. Children learned of two families —the Smiths and the Joneses. One spoke English and the other Portuguese. Now, say the Smiths (the English speakers) have a baby, and the baby immediately goes to live with the Jones family (the Portuguese speakers). When that baby grows up and learns to talk, will she speak English or Portuguese?

You can see how this experiment cleverly pits children’s beliefs about nature and language against the concept of nurture and language. Does the hypothetical child grow up to speak the language of her birth parents, which would mean that language is biologically transferred? Or does she instead speak the language of her adoptive parents, which would mean that language is learned from the environment?

Five-year-old children chose the “biological” answer. Hearing these simple vignettes, they concluded that the hypothetical child would grow up to speak the language of her birth parents, though the child lacked exposure to that language. In jumping to this conclusion, these children are following in the footsteps of the Egyptian king in Herodotus’s story—the ruler who thought that by rearing children in linguistic isolation, he could determine their “true” language. It seems that some adults may still hold on to this incorrect childhood intuition about where language comes from—and what this intuition represents.

This essay is adapted from the new book How You Say It: Why You Talk the Way You Do and What It Says About You.