For many of us, the thought of ever forgetting how to speak our native language would seem preposterous. But for some readers, it became a reality.
During a five-year captivity in Afghanistan, US soldier Bowe Bergdahl apparently lost some of his language capabilities.
This prompted the Magazine to ask under what circumstances a person could lose their native or first language.
In response, readers wrote in to tell their own stories of language loss or confusion. Here's a selection.
Kristina Schmale O'Hagan, Ireland
Having had to switch from German to English, I now realise how inextricably linked language and culture are. Being from a more reserved nation saying "Ich liebe Dich" does not come as easily as saying "I love you".
I can also swear in English... yet do not know any German expletives!
I do feel a kind of loss over a language I once was fluent in, but luckily I have reached a level of fluency in English that allows me to be fully myself.
M Rodgers, Midlothian
I moved to the UK when I was 23 and have been here for over 10 years. People always look at me sceptically when I say I have "lost" my Dutch language.
When my mother calls I need to put her on hold while I go and get the thesaurus.
My colleagues send me documents to be translated into my native language, and I end up taking them home to take my time. Even when I come across other Dutch people in the UK, I ask if they don't mind speaking English because my English is better than my Dutch.
I don't mind though, English is such a beautiful language, I have loved it since I was little and it's no wonder I ended up in an English-speaking country.
Alicja Gruszka, Italy
I was born in Krakow, Poland. I graduated in medicine and left for London where I did my PhD and stayed for two more years, then moved to Milan, Italy. Thus, I had lived for a total of eight years in London and have now lived for 10 years in Milan.
During my time in England, English became an integral part of me, up to the point that I would dream in English and respond in English first thing in the morning whilst on holiday in Poland.
I then decided to move to Italy. I learned the language in no time at all. It seemed as if I had already known it and it just needed to be given an opportunity to be used.
However, there is a clear division as to what I like to use "my" three languages for - I write my memos on all work and life-related issues in English as well as do most of my pleasure reading in this language. I write things to do with my other great passion - music - in Italian and Polish has become a spoken tongue that I use with my family and friends.
Obviously, I can still write in Polish, but I am told that my grammar or more precisely, the syntax, is very odd.
I do form neologisms that consist of an English or Italian root and a Polish ending. Some are very funny and many make no sense what-so-ever to a Polish speaker. Overall, many times do I realise that I cannot remember how to say a certain thing in my native language, which I find both frustrating and sad.
Sue Jensen, Denmark
I was born and grew up in Lancashire, UK, and at the age of 25 moved to Denmark.
Twenty-five years later my English language is sometimes a disaster - can't find the words, grammar is back to front (like Danish) and my numbers are shot at.
I run my own cheese shop where I'm in contact with the Danish public all day, every day. Giving correct change is important, so we count it out.
However Danes say their number backwards (ie nine and fifty, rather than fifty-nine), it really mixes me up sometimes. Particularly as my tables are strongest in English... sometimes I do count it out to them in English, especially on very busy days.
My Danish friends and customers are also very patient, especially when I mix the two languages, which does happen when I have been speaking only English for two to three days or more.
Lorraine Jordan, Italy
It was so interesting reading this article, as I well know that feeling of struggling to recall a specific word in English. I've lived in Italy for eight and a half years, and I work alongside fellow ex-pats at a large language school.
Amazingly it is not uncommon for one of us to begin describing a word we have been trying to think of for several hours in the hope that someone else will remember it.
The worst feeling of all is when you know the word perfectly well in your second language and seem totally incapable of remembering it your own language.
Susan, United Kingdom
I moved to the UK from Finland in 1998, when I was 17. Though I have no difficulty holding a casual conversation in Finnish (which I do regularly with my family), I have certainly forgotten words and find myself using grammar constructs that exist in English, but not in Finnish, such as starting sentences with "there are".
On many occasions, I have also caused a great deal of hilarity trying to use a word in Finnish which is in fact not a word at all, but rather an attempt to recall a word and instead making up an imaginary one that sounds a bit like it, but doesn't really exist.
All of this, ultimately, is not really an issue as 99% of the time I use Finnish in casual conversations with family members. But I have entirely lost the ability to tell the difference between the casual and formal language in Finnish and writing even very simple e-mails in the 'formal' tense is difficult. I have to ask someone to read them to make sure I'm not accidentally sending something in an overly casual tone!
Milind Sojwal, United States
I came to America from my native India 20 years ago. I could speak Marathi, my mother tongue, fluently and Hindi, the lingua franca of northern India, fairly comfortably.
In these past 20 years, I have gone to India several times and have preached in my old church in Marathi (I am an Anglican priest) several times. But I am astonished how awful my Marathi is. I speak it haltingly.
While searching for the right word I often stumble into my German (which I studied for two years in college), into my Spanish (which I have been studying for the last four years), as I am not able to hear Marathi spoken.
My wife and I only have English in common, since neither of us speaks each other's languages, even though we are both Indian.
Paulo Pinto, Southampton, UK
I was born and raised in Portugal and moved to Britain in 2010. I'm now 30 and fully immersed in British culture - I don't socialise with any other Portuguese people, only watch British TV, and my partner is British.
I've noticed more and more that I find it hard to express myself in my native Portuguese. This is more evident when I talk to my Portuguese friends about my job, as my main job references, jargon and expressions are all English.
I've also noticed I've started dreaming in English and forget the odd word. Portuguese will always be my first language by nature, but the longer I'm away the less cultural references I have.
Matous Ptacek, United Kingdom
I was born in the Czech Republic and spent the first 11 years there, not speaking a word of English.
However, once our family moved to Luxembourg and I begun to attend the European School, and then eventually started university in the UK, I've been finding my actual thought processes - not just my speech - curiously segregated.
Buying milk, cycling, looking at bugs in the park - I have to consciously try for English concepts and sentence structure to emerge. But once I start thinking about philosophical issues, or solving a scientific task - even in my head - it all happens in fluent English.
And I don't think it's just a matter of vocabulary, either - the ideas pop into my head with Czech or English structures and associations already in place, articles missing/present in the sentences depending on the subject. Perhaps mere confirmation bias, but I've had to expend conscious effort not to sound Russian at the till, while discussing geology is utterly fine!
Ingrid van de Kamp, Dubai, United Arab Emirates
I moved to the Middle East when I was 24 and have been speaking English for 26 years now. I have definitely lost the fluency in my native language.
My Dutch family and friends think it quite hilarious how I butcher my mother tongue. I make so many grammatical errors, am so often lost for words and totally mess up expressions.
It usually gets a bit better after a day or so, and I certainly try, but is very difficult to keep up when I am tired or have had a glass of wine. I clearly think, talk to myself and dream in English.
Alan Fear, Brazil
I've been in Brazil now for 22 years. I'm not losing my English but sometimes I unconsciously come out with some weird hybrid sentences.
For example "change" in Portuguese is "trocar" and "clothes" is "roupas" - a while back I arrived home and this sentence leapt out of me: "I'm just going to troc my roups and I'll be right there!"
Reka Polonyi, France
I grew up with Hungarian parents in the US and in France. My sisters and I never lived in Hungary, but we'd occasionally visit family and friends during the summer.
My parents taught us the language - as well as to read and write in it... we adamantly kept Hungarian the predominant language at home.
Meeting other ex-pat Hungarians in my childhood, I was always surprised at the strong accents and language difficulties the children had, even though many had lived in Hungary before.
I finally understood, after many years of meeting and speaking to "expat kids", that the key to retaining fluency in one's mother tongue (or at least the parents' predominant language) is to speak it with the siblings. This plays a crucial role in retaining its "freshness", its "youth", rendering it a tool in which to communicate spontaneous thoughts, insults, jokes, feelings of anger, excitement, surprise, etc.
Melker Hansson, Spain
I experienced loss of fluency in Swedish after having married a Spanish woman and moving to Spain 25 years ago.
In those days, the internet didn't exist of course and I only used my native language in a monthly phone call.
Strangely, my Swedish "came back" after becoming fluent in Spanish in about four years.
My impression is that if the brain is busy learning a new language and you only communicate in this language, the other languages you know are temporarily suppressed.
William Buchanan, United States
As an American soldier in Germany in the 1980s, I had frequent and prolonged interaction with native Germans, but my interaction with Americans was infrequent and brief. I lived with a German girlfriend off base as well.
After completing my three-year tour of duty, I returned to the United States.
Many friends who'd known me since childhood remarked on my "German accent". I was unable to hear it when I spoke, but was quite surprised when I heard audio recordings of myself since it was subtle but unmistakably there.
Within a period of three months or so after my return to the US, my "German accent" disappeared.
Pascal Jacquemain, Yorkshire
I am French. I was born in Paris 45 years ago. I have lived in England for the past 19 years.
After a few months living in Britain, I went to a hotel/restaurant in the Pyrenees that I had used before moving to Britain.
The hotel staff recognised me but hearing me speak English and an already slightly English-accented French, they were not so sure. This was 18 years ago.
Now, I struggle with my French. Understanding the language, no problem. There are situations that challenge me though.
I find it extremely difficult to discuss IT in French although I started my career in France. When I have to "think on my feet" and say something quickly, a mixture of French and English may result.
I've been living in the UK with my wife and two children for nine years and, although at home we only speak Italian, my entire work life is in English.
I teach and translate from Latin and Greek and have some fluency in other modern languages, but now I can hardly write an email in Italian.
It's not a problem of vocabulary, grammar or syntax, it's the lack of emotional involvement with the environment you relate to.
Before coming to the UK, I enjoyed reading Shakespeare or even Chaucer in the original, but had no idea of how to conclude an email.
Yiding Hao, US
My family and I left my native China when I was very young. While living in Japan, I acquired Japanese as a second native language, and after immigrating to the United States, I began doing the same with English.
But my new community in the Chicago suburbs did not have a vibrant Japanese community, and I had no contact with the Japanese language.
One year later, when I was six years old, I overheard two ladies speaking in Japanese and noticed to my dismay that I could not understand. The language had quietly slipped away.
Eight years later, I began to watch Japanese television shows in an attempt to re-immerse myself into the language. My efforts were mostly in vain.
I have some proficiency in Japanese today, but everything I know about that language has been consciously learned, as if Japanese were never the language of my thoughts and dreams.
I find the term "language attrition" very useful. A native speaker of English, I spoke French almost exclusively from the age of 17 to 30, and when I re-entered Anglo society found myself continually grasping for words or using odd Gallic phrasings, often to much amusement.
Having also learned Chinese in the interim was a further complication, but pertinent in the case of my children who all spoke Chinese as a first language until entering school, when English laboriously took over.
They now still understand very well, but have difficulty speaking.
Meanwhile, my own French went to the background for a dozen years, and now that I am back in a Franco environment, I stumble frequently.
It is interesting to note, however, that my reading and writing skills never seemed to diminish during these "linguistic shifts" - only immediate oral production has caused problems.
Alexandra Whitaker, Spain
I am a native English speaker. When I was 24 I moved to the Basque country, where I studied Basque intensively and picked up Spanish on my own.
For three years I spoke no English. When I met an English tourist after that time, I found that my mouth ran away with me, and I said comic-book things like "in the house of my friend" and "I live here since three years ago."
But the most puzzling was one night trying to write a letter to my parents. I couldn't remember how to spell "ought." I tried it many ways in the margin to see which looked correct: "haut, aught, aut, hought."
In the end I settled for "ot", even though it seemed a little short.
Heru Reksoprodjo, Finland
Born and raised in Indonesia, I grew up in a household where many languages are spoken, albeit in only phrases. My main language is Indonesian, although my mom also spoke Dutch, having lived there for 20 years during her previous marriage, and my dad spoke German, where he studied. Together they also spoke Javanese, also a language used by my grandparents.
At the tender age of 16, I moved to the US, where for a year I was cut off from my compatriots. The following year, I started college.
Fast forward 14 years, I was on the brink of yet another jump across the ocean, this time to Finland with my spouse. After a six-month shock immersion in a non-English speaking environment deep in the northern forests, I started a job at a technical university, where English is widely used.
Here, nine years later, although still fluent in Indonesian, I am unable to speak it actively, only as a responder.
Thus, my own kids are not exposed to the language. On the other hand, my Finnish skill still has much ground to cover to be even able to be considered functional.