Every year on 23 September, the world marks the International Day of Sign Languages. It sits inside a longer stretch, the International Week of the Deaf, and most people who don’t use sign language day to day will scroll past it without a second thought. That’s understandable. It’s easy to overlook a day built around a language you’ve never needed.

But step back for a second and the day says something bigger than it first appears to be. Sign languages aren’t just spoken language translated into gestures. They’re completely redefined as full languages, with their own grammar, their own rhythm, their own way of building meaning, and they differ from country to country the same way spoken languages do.

A deaf person from one part of the world can’t just sit down with a deaf person from another and instantly understand each other, unless both happen to know the shared, simplified sign used at international gatherings, which works more like a common shortcut than a real shared language.

For a huge number of people, none of this is trivia. It’s how they get through a doctor’s visit, a job interview, a classroom, a call with family, a genuine moment of connection with another person. When that access isn’t there, a lot goes missing along with it: schooling, healthcare, job opportunities, even the basic experience of being understood in a room full of people.

Which is really the point of the day, once you sit with it. It isn’t asking hearing people to become fluent overnight. It’s asking for something smaller and, in a way, harder to admit we’ve been skipping: the acknowledgment that communication was never meant to be one-size-fits-all, and that being understood shouldn’t depend on how close you already are to the “default” way people expect you to talk.

Most of us never think about this, because we’ve never had to. Every service we call, every form we fill in, every meeting we sit through, quietly assumes we can hear and speak the way most people around us do. That assumption is invisible right up until you’re standing on the other side of it, watching a conversation happen without you in it.

Sign languages also carry something beyond communication. Deaf communities have their own humour, their own storytelling traditions, their own sense of shared history, all built and passed down through a visual language rather than a spoken one. Treating sign language as a workaround for something “missing” misses this entirely. It isn’t a substitute for speech. It’s its own language and its own culture, one that happens to have spent a long time fighting to be recognised as equal rather than lesser.

This year’s theme leans into exactly that, centring on deaf people’s human rights, timed to the anniversary of the international disability rights treaty that first put sign language on equal legal footing with spoken language. All these years on, equal footing on paper and actual equal footing in daily life are still two different things in a lot of places.

None of this needs a grand gesture today. Mostly it just needs noticing. Learn to fingerspell your own name. Look at the deaf person speaking, not just at whoever is interpreting for them. Don’t assume someone who signs also lip-reads, or wants to. Ask rather than guess what works for someone. Treat captions and interpreters as normal, not as an inconvenience someone has to justify. Teach a kid a handful of signs the same easy way you’d teach them a word in another language.

Language is usually the thing that lets people in. For a lot of the world, it’s still the thing keeping people out, not because sign language doesn’t work, but because so few of us ever learned any of it or made room for it.

So on 23 September, the task is a small one. Notice a language you’ve probably never had to use. Learn a sign or two. Make space for someone to communicate the way that actually works for them. It won’t fix everything on its own, but it’s the kind of ordinary gesture that adds up, the same way being shut out adds up too, one small oversight at a time.