🧠 Waking Up a Foreigner: How Anesthesia Can Make You Forget Your Native Language
He Woke Up From Anesthesia Speaking English: A Dutch Teen’s Story and the Brain’s Mystery
Hi! It’s me again, the lead author of the MedAssist AI blog. Today’s story sounds like the opening scene of a Hollywood thriller or a sci‑fi novel. But it’s not fiction—it’s a real medical case that once again makes you admire (and slightly fear) how complex the human brain really is.
Picture this: a 17‑year‑old boy in the Netherlands—an ordinary high‑school kid—injures his knee playing soccer. Nothing dramatic, but he needs a routine orthopedic surgery. His first operation ever. He’s on the table, the anesthesiologist does their job, the surgeon does theirs. Everything goes as planned.
Then he wakes up… and it’s strange.
He regains consciousness, but he’s disoriented. He doesn’t recognize his parents, who are anxiously peering into his eyes. He doesn’t understand a word of Dutch—his native language, the one he’s spoken all his life. Instead, he starts speaking English, insisting he’s in Utah, USA—a place he has never been.
This isn’t a “doctors’ lounge legend.” It’s a carefully documented case report—“Lost in another language: a case report” by Husam K. Z. Salamah and colleagues—published in the Journal of Medical Case Reports in 2022.
Today, we’ll put on our scientific‑detective hats and figure out what happened to this boy—and why the brain sometimes pulls off tricks like this.
What Was That, Doctor? Meet Foreign Language Syndrome
What happened to the Dutch teen has a scientific name: Foreign Language Syndrome (FLS).
It’s an extremely rare phenomenon in which a person, after surgery and anesthesia, temporarily loses the ability to speak their native language and “switches” to a second language—one they learned at some point, but may not have used actively.
Key features of this syndrome:
- Sudden onset: Usually right after emerging from anesthesia.
- Temporary: The episode lasts from a few minutes up to a day, after which the native language returns on its own.
- No structural brain damage: Follow‑up exams typically show no organic lesions.
It’s important not to confuse this with another (more famous, but still rare) condition: Foreign Accent Syndrome (FAS). With FAS, a person continues speaking their native language, but the pronunciation, rhythm, and intonation shift so much that others perceive it as a foreign accent.
FAS is most often linked to stroke or traumatic brain injury—meaning real damage to speech centers. FLS is a different story altogether, and the main suspect here isn’t the surgeon’s scalpel—it’s the anesthesiologist’s syringe.
The Maastricht Patient: A Detailed Breakdown
Back to our 17‑year‑old hero. His case is notable because it’s one of the first well‑described FLS episodes in an adolescent—most previous reports involved adults.
What do we know about him? He’s Dutch and speaks the Limburgish dialect. He learned English in a regular school, like millions of other kids, and never used it outside the classroom. No relatives in English‑speaking countries. No recent travel.
And yet, after knee surgery, for 24 hours he can’t string together even two words in Dutch. Nurses and doctors are baffled. A psychiatrist is called in.
During the evaluation (which, naturally, is conducted in English), it turns out the boy is generally coherent—cheerful, engaged, cooperative—but he cannot speak his native language. He also remembers that he didn’t recognize his parents and genuinely believed he was in America.
The most interesting part came about 24 hours post‑op. Friends visited him in his room. And while talking to them, he suddenly—effortlessly—started speaking Dutch again.
As if a switch in his head clicked back into place.
Follow‑up workups—including detailed neuropsychological testing almost a year later—found no abnormalities. Memory, attention, reasoning: all normal.
The only complaint he reported was a subjective feeling that it became harder to concentrate after surgery. Testing didn’t confirm it.
A mystery, plain and simple.
He’s Not Alone: A Brief History of FLS in Medicine
The authors also reviewed other published cases—and a curious pattern emerges.
- Sex and age: Almost all patients are men, most older than 50.
- Type of surgery: Often orthopedic procedures (as in our case).
- Languages: In many reports the native language was English, and patients “switched” to Spanish, French, or Hindi.
- Anesthetics: Three drugs show up again and again: propofol, fentanyl, and midazolam—very common components of modern anesthesia.
- Memory: About half of patients later couldn’t remember speaking the other language; the rest, like our Dutch teen, did remember the experience.
One case is especially telling: a 28‑year‑old man began speaking Spanish after surgery—a language he learned in elementary school and never used. It turned out he’d had similar “switches” to Spanish before, but under different circumstances—during severe alcohol intoxication.
That points to an important idea: FLS may be less about language itself and more about an altered state of consciousness in which the brain stops running its usual routines.
The Main Suspect: Anesthesia or Delirium?
So what’s happening in the brain at that moment? Why would it “turn off” the native language—polished over years of everyday use—and “turn on” a second language that’s far less fluent?
Researchers still don’t have a definitive answer. But the main hypothesis—also supported by the case report authors—links FLS to a condition called emergence delirium (ED).
Delirium is an acute disturbance of consciousness characterized by impaired attention, disorientation, and sometimes hallucinations. Emergence delirium is relatively common—especially in children and older adults.
A child may wake up from anesthesia screaming, flailing, not recognizing their parents—and then calm down and return to normal half an hour later, as if nothing happened.
The authors suggest that Foreign Language Syndrome isn’t a standalone disease, but a very specific and rare variant (phenotype) of emergence delirium.
Arguments for this theory:
- Same timing: Both FLS and ED occur right after anesthesia.
- Similar symptoms: Confusion and disorientation show up in both. An FLS patient who doesn’t recognize family and believes they’re in another country is a textbook delirium picture.
- Similar course: Both resolve on their own without specific treatment.
In other words, the “language glitch” may be just one symptom of a broader temporary disruption—brain chaos during the reboot after anesthesia.
How Does Anesthesia “Switch” the Brain?
Okay—let’s say it’s delirium. But what’s the mechanism behind the “switch”? Here we step into the realm of hypotheses, but they’re fascinating.
General anesthesia isn’t just deep sleep. It’s an artificially induced, reversible coma—an intentional suppression of brain activity. When the drugs wear off, the brain “reboots,” but that reboot may be uneven.
-
Hypothesis #1: Uneven waking. Different brain regions and networks may emerge from anesthesia at different speeds. Imagine the network for your native language (L1) as powerful, complex, and energy‑hungry. The network for a second language (L2) may be simpler and less practiced. After the “shutdown,” the heavy L1 system might take longer to come back online—and during that window, the lighter L2 system takes the lead. The brain, trying to restore communication, uses whichever tool becomes available first.
-
Hypothesis #2: Disrupted connectivity. Modern research suggests anesthetics affect not so much individual areas, but the connections (connectivity) between them. Anesthesia may temporarily break the familiar neural pathways used for the native language and activate detours—rarely used routes associated with the second language.
Both hypotheses point to the same conclusion: the brain isn’t a hard drive with neat folders labeled “Dutch” and “English.” It’s a dynamic, constantly changing network. Languages likely aren’t stored in isolated boxes, but as overlapping, interacting neural ensembles.
FLS is a rare chance to peek “under the hood” and see what happens when the usual order breaks.
What Does This Mean for the Rest of Us?
First and foremost: don’t fear that after your next dental sedation you’ll start quoting Shakespeare and forget your native language. Foreign Language Syndrome is so rare that most anesthesiologists never encounter it in their entire careers.
Second: this phenomenon is a brilliant illustration of how plastic—and how mysterious—our brain is. It shows that even something as fundamental as your native language isn’t an untouchable constant; under certain conditions, it can be temporarily pushed into the background.
And third—the most important point. Cases like this remind us that even a “routine” medical procedure is still an intervention into the most complex system we know: the human body. Medicine can control a lot, but there’s always room for individual reactions and unexpected outcomes.
That’s exactly why MedAssist AI exists—to help you understand these reactions and make sense of the complex (but fascinating) stories your own body is writing.
We help you decode the language of your body—whether it’s lab results or unusual symptoms—so you can walk into a doctor’s appointment prepared and speak the same language. No matter which language your brain temporarily decides is “native.”
