Is learning a language like riding a bike? Well, yeah, if you consider the fact that you’re probably going to look a tad clumsy the first couple times you try it. And additionally, yes from the standpoint of “you never truly forget once you learn” — but therein lies the caveat. What does it mean, in this case, to truly learn a language? And how well do you have to learn it to have this semi-permanent ability to recover your knowledge? Second language attrition, or the process of slowly forgetting a second language, spares few people who let their language go unpracticed for a long enough period of time. But the rate and timing with which it sets in is variable.
Though there’s no one-size-fits-all answer (or guarantee that your burgeoning Swedish skills will still be there for you if you let them collect dust for two years), there are ways to estimate how quickly you’ll forget a foreign language if you stop using it.
What The Studies Say
Second language attrition has been examined from a scientific standpoint, and the general consensus seems to be that your level of proficiency is going to make a big difference in how long you’ll retain your language knowledge after you stop practicing. When information makes it into your long-term memory — or when you don’t have to strain your brain too hard in order to speak — you’ll probably be able to get back to your previous level of fluency with just a bit of elbow grease and practice in the future.
Various research has pointed to a few consistent variables that can influence the rate of second language attrition any given individual experiences. One is age (both how old you were when you learned your language, and how old you are now). Another is how often you use the language, as well as how long it’s been since you’ve last used it.
One study examined native English speakers who had learned Hindi or Zulu during their time spent abroad as children. Though they were unable to remember specific vocabulary words, these subjects were able to recognize phonemes more easily than subjects who hadn’t spoken those languages as children.
“Even if the language is forgotten (or feels this way) after many years of disuse, leftover traces of the early exposure can manifest themselves as an improved ability to relearn the language,” wrote the study authors.
Another study examined second language attrition in French students who had been enrolled in an intensive six-week course (so, a different level of exposure than the expatriate kids). When the same students filled out a questionnaire six months after the course, there was no attrition in reading skills, but speaking and understanding skills both suffered, suggesting that there are some facets of fluency that may be easier to retain than others.
And as it turns out, you don’t necessarily need to wait six months to see a decline in language skills. Many teachers likely experience this firsthand when students return from summer break having forgotten some of what they learned the previous year.
One study specifically examined the rate of attrition in French skills by 12th grade students over summer break. Many students rated their skills as weaker following vacation, though some skills actually managed to improve, especially depending upon the student’s motivation to practice over the summer. Grammatical accuracy was one area that generally declined.
What People Say
Though anecdotal evidence is less reliable, it can help paint a picture of how second language attrition actually plays out in real situations.
Here is what a few Quora users had to say about the forgetting (and the remembering) of their language skills.
“I moved to France from the USA when I was 12. I learned to speak French fluently by the end of the first school year. By the time I was 15, I was ranked at the top of my class. Then I moved back to the States. I took the AP French language test after one year of not speaking French and scored a 5/5. After 3 years I started the AP French literature course at my high school, but it felt awkward and I lost interest in the program and never took the test. After 10 years, I attended a college summer session in Paris and discovered that my French was a lot rustier than I had anticipated. I struggled with vocabulary, grammar, and conversational cadence. But, by the end of the month, I had regained almost all of my French aptitude. Win! It has now been almost 20 years since returning from France. I still have a good French accent, and I still have the basics of conversation. My grammar stinks, my vocabulary is in the toilet, and my ability to learn French on the fly, contextually, is rusty. BUT, give me another month and I’ll be back at 100% in no time.” – Margot LaNoue
“I learned Mandarin Chinese as my third language at 4, went to a Chinese elementary school, after which while in Asia read a lot of Chinese books for fun, but after at 17 moving to western Europe to study couldn’t practice speaking it anymore since nobody around me at that time spoke the language. After the first 10-20 years I felt my command of Mandarin Chinese slipping away, at present after retirement am taking private Chinese conversation lessons to brush up my Chinese language skills, after three years am able to hold simple conversations again, my poor vocabulary (as seen by me at the level of a university graduate with lots of postgraduate training) is still a major problem. Am more or less back at the elementary school level.” — Liang-Hai Sie
“I learned Russian in school, didn’t use it at all for 25 years, and then was able to recover good-enough mastery while listening to one language tape for a few weeks before visiting Moscow. I tried one language tape to learn Spanish, which I have never ‘learned,’ and it was a bust.” — Karen Tiede
“I speak English, Russian, and Ukrainian. I left Ukraine in 1994 and returned there once. I can still speak Ukrainian, but it takes a lot of effort. I don’t remember how to pronounce certain words and my accent does not sound native. However, when I went back to Ukraine for a few weeks I got back to being able to speak it quickly.” — Leonid S. Knyshov