The problem lies in the fact that the job is a lectureship for teaching German. I’m German myself, as is she, and so I felt I should write the letter in German.

I couldn’t do it.

First off, I no longer trust my German spelling. This is partly because the spelling rules have changed in the 20 years since I left, partly because I spoke and wrote Dutch for a long time, where many words sound quite similar but are spelled differently, and partly because my knowledge has simply eroded. What’s more, words elude me and I’m often no longer sure if they mean exactly what I think they mean.

My grammar is restructuring itself along the lines of English, which in German translates to simpler, less sophisticated sentences. None of this, I felt, would shine a good light on the candidate.

I’m not alone in experiencing this. Having spent any length of time – and this can be as little as a few months – in a foreign context, expats like me tend to feel like fish out of water or, perhaps more accurately, like sea lions out of water: we can survive, yes, but movements that otherwise are natural, fluid and efficient become a huge effort. We flap, we fumble, we wobble along, feeling and looking slightly ridiculous.

In linguistic terms, this means that we um and ah a lot more. We pause more often. Our sentences go wrong in the middle, and we have to backtrack. Our vocabulary becomes less sophisticated, and our grammar less complex. And there are more subtle effects, to do with the different ways in which politeness and social interaction differ across languages.

For example, English has only one pronoun – “you” – to address others. Many other languages make the distinction between a familiar and a formal or polite pronoun: for example, French tu and vous, or Spanish tu and usted. There are no clear, straightforward rules telling you in which context to use a formal and in which a familiar pronoun, and what is considered appropriate and polite varies hugely between countries.

For example, in the Netherlands I became used to addressing the Rector Magnificus of my university with the informal pronoun and by his first name. In Germany, one was expected to call him Your Magnificence (I’m not making this up). Using a familiar pronoun, let alone a first name, would have been unthinkable. Not only have conventions changed over the past 20 years, but I feel that I’ve entirely lost my sense of what’s appropriate in any given situation.

Many of these phenomena of what is called language attrition are quite similar to the changes in language use often found in the very early stages of dementia – although, of course, the underlying cognitive processes are completely different. Language attrition is not a neurological condition, but comes about because two languages are fighting it out in one brain. Like people living with dementia, those experiencing language attrition are faced with the stark reality that we assess and judge people based on how well and how confidently they use language. When linguistic performance becomes compromised, intelligence, capability, and overall cognitive functioning are underestimated.

Unlike people living with dementia, people with language attrition may take comfort in the fact that these symptoms are unlikely to persist or get much worse, and that reimmersion in the native language will probably make them disappear within a few weeks.

But for 3 million EU citizens living in the UK and 1 million Britons on the continent, many of whom may now be contemplating a return to their home country because of Brexit, language attrition could be a real problem. A badly spelled or clumsily worded letter of application, a fumbling and hesitant performance at interview, or – horror of horrors – an inappropriate use of a pronoun or a first name, or the omission of a honorific title, may ruin any chance to prove yourself in the job. Such errors are, of course, completely unrelated to how competent you are to carry out a particular function – but that will not provide much comfort if language attrition has cost you the job of your dreams.

So what should you do if you are thinking of going back on the job market in the country of your birth? Here are some tips that may come in handy:

• Always have all documents you submit checked by a fully competent native speaker who is currently living there.

• Think yourself into the language, starting as early as possible. Play out the conversations you may expect to have in the job interview. Consider not only specialised key terms but also the ways in which you will interact with the members of the panel. Do this out loud.

• If possible, look up who the panel members are and what their titles are. If you are unsure, ask a fully competent native speaker what the proper way is to address them. Practise this.

• If you are unsure about certain technical terms or specialised vocabulary, make a cheat sheet for yourself, and don’t feel embarrassed about referring to it during the interview.

• If you can, arrange a mock interview with friends or family who share your native language.

Some of this may seem over the top – but it could make the difference between you feeling like a graceful sea creature in its element or a clumsy lump of lard wobbling along on dry land.