Donders Wonders Blog

Does the memory of your mother tongue last forever, or can it be swept away with time?

Can you forget your mother tongue?

A lot of people assume that you can’t forget your mother tongue. However, although traces of it may persist forever, it is entirely possible to lose the ability to communicate in your native language. Here, we explore why and how this happens.

This post is also available in Dutch.

After high school I moved from the U.S. to Argentina, where I was met with jealousy that my command of English meant that I didn’t have to study for a TOEFL or Cambridge First Certificate exam. Eager to eternalize my privilege, I remember asking my mom if she thought I should take one anyway, you know, before I lost my English. She thought I was being ridiculous. After all, you can’t forget your mother tongue, can you?

Nothing you learn is ever truly lost

The answer is: it depends on what you mean by “forget.” According to researchers of language forgetting or attrition, what we “lose” is the ability to access and retrieve the memory, rather than the actual memory. Studies on international adoptees1 have shown that even infants who were adopted before they learned to speak show traces of having been exposed to the sounds of their mother tongue (L1) by relearning them faster. So one could argue that you never truly lose a language.

On the other hand, it is entirely possible that, having fully acquired your first language, and in the absence of any brain damage, you lose the ability to communicate in it. The most common examples are people who were raised speaking another language at home which they stopped using as they grew up, or people who moved abroad and lost command of their mother tongue2. Most researchers agree that language attrition is usually brought about by, as in these examples, lack of use and interference from another language (e.g., see this recent article by Donders researchers).

Research on children who were adopted internationally has revealed that your mother tongue may leave lasting traces on your brain.

Photo by Colin Maynard on Unsplash (license).

Forgetting is not an all-or-none phenomenon

Forgetting your L1 need not be so extreme and can occur in many shapes and forms such as: struggling to remember a word, having a restricted vocabulary, confusing a saying or metaphor, spelling or pronouncing a word wrong, using non-native grammar, speaking disfluently, or developing a foreign-sounding accent. What exactly is forgotten and how much depends on many different factors.3

On the one hand, productive skills (speaking and writing) are said to go before receptive ones (listening and reading comprehension). Some aspects of language have also proven to be more resilient than others, with grammar outlasting vocabulary, for example. Even within vocabulary, common words and cognates (translations with a similar form across languages, such as the English “nose” and Dutch “neus”) tend to outlive infrequent and non-cognate words. On the other hand, there’s also the new lingo that was coined after a migrant left, which they are overall less likely to know.

After more than 50 years of residence in the U.S., Arnold Schwarzenegger is often said to sound like a foreign speaker of his native German. An ongoing study at the University of Graz has found evidence of English influence on his mother tongue.4

Photo by Gage Skidmore via flickr (CC BY-SA 2.0).

“Use it or lose it”

Your process of language forgetting also depends on your particular language use patterns. Frequency and recency of use have been found to play important roles in predicting forgetting. For example, just learning a new language at home will have a different effect on your mother tongue than moving to a country where you hardly ever use it. Both of these are also different from moving somewhere where you still use your L1 frequently, whether at home or because it’s a lingua franca (a common language among people with different native languages). In normal circumstances, people don’t just forget their mother tongue from one day to the next, but rather gradually, as their new language becomes more dominant. In addition, factors such as motivation and identity are thought to play a role.

Our ever-changing language

In addition to these reasons, frequent communication with non-native speakers or with a limited number of native speakers in your L1 may add an additional source of attrition. As we know from a previous blog, people copy each other, some more than others. This can result in people changing their regional variant or even adopting a foreign one. Moreover, communicating with speakers of other variants or mother tongues may lead to other adaptive mechanisms to increase comprehensibility such as using commonly known words or clearer speech.

As this episode of “How I met your mother” demonstrates, our own personal language use is ever-evolving.

Although some people experience their language change negatively, feeling like they’re losing their identity and becoming a foreigner in their own language, it’s not necessarily a bad thing. Language interference is natural and just a sign that you know more than one language, while adaptation might mean that you’re an accommodating person. But if you do want to make sure you don’t lose your mother tongue (or any language, for that matter), make sure to keep using it!5

In summary: I was right; I did lose “my” English (the way I used it at that moment) and 13 years later Americans often ask me where I’m from. However, today I embrace my funky English because it tells the story of where I’ve been and who I am, much more than any English certificate could.


1Children who are adopted by guardians from another country.

2Attrition researchers tend to draw a distinction between attrition in adults and children, which tends to be more drastic. Why exactly this is, however, remains unknown.

3There’s also a lot of variability between people (individual differences), something that attrition researchers are still trying to explain.

4A similar longitudinal study found evidence of English influences on tennis player Steffi Graf’s native German.

5According to researcher Monika Schmid, L1 adult attrition can usually be quickly reversed.


Author: Mónica Wagner 

Buddy: Francie Manhardt

Editor: Christienne Gonzales Damatac

Translator: Wessel Hieselaar

Editor translation: Felix Klaassen

Featured image by Heather Shevlin on Unsplash (license).

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