It was my beginners’ class, the first I had ever taught and the main reason I have enjoyed it ever since. Sonia was lovely, always smiling, unfailingly attentive, punctual, and willing. But stone me, she was hopeless.

All of us, it is said, have the ability to learn a second language, if only the teaching is proficient. I have disingenuously chivvied despondent classes with the half-truth that, if the majority of the 56 million people in the British isles can communicate satisfactorily in English, then anyone can.

So was Sonia’s failure my fault? I suspected it was. This was my first attempt to teach English as a foreign language. Perhaps I was asking too much too soon, setting my students up to fail? Perhaps some forgotten nugget of theory proffered in training remained unexploited?

I sought advice from more senior staff. My director of studies was especially helpful; I am still using some of his techniques three years on.

They worked a treat. Except for Sonia. As the rest of this bright class sped onwards to Elementary, as some of them got a tenuous finger hold on Pre-Int, Sonia languished in the early pages of the book, smiling blankly at classroom language and introductions.

She struggled with the very concepts of textbooks and language learning. It seemed a genuine surprise to her that, having just tackled question 2, we should now attempt question 3. When Toru said, “My name is Toru,” and Jessica riposted, “My name is Jessica,” she could not see the gauntlet thrown before her and say, “My name is Sonia.”

I went back to my colleagues and director of studies, my bafflement now coloured by regrettable cruel jibes.

Sonia did not seem otherwise unintelligent. I had worked in Taiwan, her country, and had an inkling of the cultural issues involved. Besides, the aforementioned Jessica was from Taiwan too, and by now she was jostling with a couple of others for top of the class.

I would love to say that, like an EFL Sidney Poitier, I had a moment of revelation, saw what Sonia really needed to bring her to her full potential, and received a handmade “thank you” card when the term ended. No such moment came. I did in fact receive the card though. The writing inside was that of a student who has been learning English for days, not months.

I believe - in some dark way, I hope - that every teacher, of whatever discipline, at some stage in his or her career meets a Sonia; a student who, for no apparent reason, does not, will not, cannot, get it.

Perversely, our Sonias keep us teaching. Perfectionists that we are, we reflect on our practice. We look for what we did wrong, what we could have done better. Often the answer to the former turns out to be, nothing.

That’s just how Sonia is. But the answer to the latter is nearly always, lots. Galvanised, we take it back into the classroom, and pass it on to our remaining students, who will never know how much they, and therefore we, owe poor Sonia.

All the same, mentally, we wish her a safe journey home, and tell her not to hurry back.

SEAN COSGROVE Sean Cosgrove has taught EFL for the past 10 years