Since 1998, 22 October has been designated as International Stammering Awareness Day, an opportunity for the general public to learn what a psychologically complex impediment stammering is. If my personal experience of having a stammer tells me anything about attitudes nationwide, a day like this is still necessary. Even though few people are consciously prejudiced against stammerers, even fewer know much about what it is like to actually have a stammer.

Many people might find it hard to imagine their vocal cords seizing up mid-sentence. But nobody is fluent all the time, and it’s not only cartoon characters who can’t get their words out when frightened. Everyone knows what it is like to feel social anxiety, you don’t need too much imagination or empathy to recall a time when anxiety has grabbed at your vocal cords.

Many stammerers, myself included, can speak fluently when relaxed. My semi-frequent reprieves actually inspired one of the strangest and funniest instances of prejudice I have ever experienced. As I sat reading in my school library, a boy came up to me with a face like Poirot on the brink of an accusation, and said “I know your game. I know you don’t actually stammer. You just put it on. Sometimes you speak entirely fluently!” I was, unfortunately for his hypothesis, lost for words.

Though I found this boy’s confusion laughable, I now see that he had strayed on to a serious point. That I should possess the capacity for fluent speech but not be able to speak fluently all the time baffled him greatly, but it baffled me more. When I was very young I assumed there must be a fault in my speech-making machinery – the conclusion that speech theorists drew for millennia. The Greek orator Demosthenes liked to walk round with stones in his mouth, not to give himself an excuse for stumbling over his words but because he thought doing so would cure his stutter. Francis Bacon thought a stammerer’s tongue was unusually cold and heavy, and that warming it with wine would do the job: I have tried this trick many a time, sadly I can confirm it’s only a temporary solution.

The eventual realisation that my impediment was merely psychological was painful. If it was just my mind stopping me from speaking then, surely, it was possible for me to change my mind. It was my fault that I had not changed it already. I can still think this way on occasions, but generally the agency I have over my stammer makes me optimistic. Unlike the depressive, who has the ability to choose who to “come out” to, the stammerer is forced to come out to every stranger he or she meets, and so often this fear of being seen to stammer is what catches the words in one’s throat. The best way I have found of quelling my stammer is to cultivate an attitude of extreme indifference about whether I stammer or not.

It will probably strike readers as bizarre that many stammerers are not entirely ungrateful for their impediment, myself included. Those writers who stammer generally agree that it has increased their enthusiasm for language. The Welsh poet Owen Sheers has said that having to avoid certain words forced his mind to work like a “hyper-speed thesaurus”, constantly searching for words he could say, and John Updike said, “You write because you don’t talk very well … Maybe one of the reasons I was determined to write was because I wasn’t an orator.” I imagine that for the non-stammerer, language must be a little like air, a medium so compliant that most of the time you forget you’re moving within it. But for the stammerer, speaking is like moving through water – you are constantly aware of language because it constantly resists you. Having always to navigate around difficult sounds gives you a sense of how many routes a sentence can choose on its way to a full stop.

If I could use Stammering Awareness Day to give one piece of advice to those unaffected, it would be this: never, ever finish a stammerer’s sentence. You may think you’re doing them a favour, but you’re not. You’re just telling them you think their stammer is a problem, and that they are wasting your time. A stammerer’s ideal interlocutor is someone who doesn’t acknowledge their impediment any more than they would an unfamiliar accent; someone who doesn’t beam encouragingly, or look the other way, or softly murmur “take your time”. The only exception to this rule is if the stammerer would like your help implementing whatever technique they use to control their speech by reminding them to use it.

When people want to congratulate a minority they sometimes say it has “found its voice”. Stammerers already have a voice, and 22 October is a reminder to everyone else to listen to it.