Learning another language can feel a little like making new friends. Some words are immediately familiar. Others take time to get to know. And then there are the false friends: words that look reassuringly familiar but turn out to mean something quite different.

Linguists use the term false friends, or, in French, faux amis, for words that look or sound similar across languages but differ in meaning. They can be a source of confusion, but they also reveal something interesting about how our minds process language.

Linguistic Look-Alikes

First, the good news is that familiarity really can help. Words sharing a common ancestor are called cognates. English night, French nuit, German Nacht, and Swedish natt, for example, can all be traced back to the same linguistic family. The same goes for English book, Dutch boek, and Norwegian bok. Cognates are like linguistic cousins. Their resemblance in sound, spelling, or meaning gives language learners something to grab onto. The more closely related two languages are, the more of these helpful similarities they are likely to share.

But when learning another language, our brains don’t always know when a shortcut is reliable. Consider French avertissement. It looks just like the English advertisement, but instead it means “warning” or “caution.” An advertisement is une publicité. The resemblance between the two words is therefore tempting, but misleading.

This is where false friends become psychologically interesting. When we encounter something unfamiliar, we don’t process it from scratch. We draw on what we already know, using patterns, context, and previous experience to generate predictions about what a word might mean. This reflects a broader process known as cross-linguistic influence: when people know more than one language, knowledge from one language can affect how they process another.

For bilinguals and language learners, this means that words can activate information from more than one language. Research suggests that when bilinguals encounter a word, their brains can activate related words in both languages, even when they’re only using one (Ryskin, 2023). Predictable words are generally easier and faster to process than unexpected ones. But the same shortcuts can sometimes lead us astray. A familiar-looking word can activate a meaning that turns out to be wrong for the language or context we’re actually using.

When Words Fool Us

False friends can produce some memorable mistakes. Spanish embarazada looks suspiciously like English “embarrassed,” but it means “pregnant.” The Spanish word for embarrassed is avergonzado or avergonzada. These are reminders that a familiar-looking form does not guarantee a familiar meaning.

Many well-known false friends have a decidedly taboo side. The Swedish word bra means “fine” or “well.” So, an English speaker encountering bra in Swedish might momentarily think they’ve wandered into a conversation about underwear, only to discover that everyone is actually talking about something being good. The two words aren’t related. The Swedish word bra comes from an older word braf, meaning “good” or “brave,” while the English bra is a shortening of the French brassiere.

The Upside of Getting It Wrong

These mistakes are a natural part of learning another language. They show that the learner is actively making connections between their known language and the new one. The problem is that sometimes the connection is stronger than the difference. Research on false cognates suggests that the overlap in word form can actually help learners acquire new vocabulary, even when that same overlap can occasionally lead them astray. (Otwinowska, 2021)

That is one reason false friends are so revealing. They show language learning in action. The brain is constantly comparing, connecting, predicting, and updating. Occasionally, however, the familiar-looking word leads us down the wrong path. Language learning therefore requires more than memorizing vocabulary. It also requires learning when to question our first impression.

After all, in language, as in friendship, familiarity doesn’t always tell the whole story.