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International Day of Sign Languages: why 23 September Matters

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Graphic for International Day of Sign Languages, featuring bold text that reads ‘International Day of Sign Languages’ with the theme ‘No Human Rights Without Sign Language Rights… 23 September’. On the right, a woman signs in conversation with another person. A small logo of two overlapping hands is shown in the corner.

International Day of Sign Languages: History, Rights, and How to Make Access Real

Every year on 23 September, communities around the world celebrate the International Day of Sign Languages (IDSL) — a moment to recognise sign languages as natural, fully-fledged languages and to champion the rights of Deaf people everywhere.

The UN General Assembly created the day in 2017; the date honours the founding of the World Federation of the Deaf (WFD) on 23 September 1951. The first IDSL was marked in 2018, and it now sits within the International Week of Deaf People.

How many sign languages are there?

There’s no single global sign language. In fact, there are hundreds. The UN (drawing on WFD data) notes more than 70 million Deaf people worldwide, over 80% living in developing countries, and “more than 300” different sign languages in use. Linguistic databases such as Ethnologue document at least 150+ distinct sign languages — and researchers suspect more remain under-documented.

Quick myth-buster: sharing a spoken language (e.g., English) doesn’t mean sharing a sign language. BSL and ASL are not mutually intelligible and come from different language families.

Are sign languages “real” languages?

Yes — and the modern field owes a lot to William Stokoe, whose 1960 work helped mainstream linguistics recognise sign languages as fully linguistic systems with their own phonology, morphology and syntax. A big shift in thinking, and a big step for Deaf language rights. 

A (very) brief history of sign languages

  • 18th century France – Abbé de l’Épée founded the first free public school for Deaf people in Paris, building on signs already used in the community. His work influenced Deaf education across Europe.
  • 1817, United States – Thomas Hopkins Gallaudet and Laurent Clerc founded the American School for the Deaf; ASL developed through contact between French Sign Language (LSF) and existing community/home signs in the U.S.
  • 19th–20th centuries, Martha’s Vineyard – A famous signing community where Deaf and hearing residents all used sign language in daily life — a reminder that when a language is shared, barriers fall.
  • The BANZSL family – BSL, Auslan (Australia) and NZSL (New Zealand) are related and share a two-handed manual alphabet; they’re a family of closely related languages, not dialects of ASL.

The UK context: recognition of BSL

The UK Government formally recognised BSL as a language in 2003 (a policy statement at the time, not a legal right). In 2022, the British Sign Language Act gave BSL legal recognition in England, Scotland and Wales, and requires government departments to report on how they use BSL in public communications, guided by a BSL Advisory Board. Progress — and more to do.

How many people use BSL? Census 2021 recorded 22,000 people in England and Wales reporting BSL as their main language; UK Government reporting rounds this to about 25,000 across the UK. (The “main language” measure is conservative, so the wider community of BSL users is larger.) 

Sign language rights in international law

The UN Convention on the Rights of Persons with Disabilities (CRPD) explicitly recognises and promotes the use of sign languages. Article 21 calls on States to accept and facilitate their use in official interactions; broader articles protect linguistic and cultural identity. In short: no human rights without sign language rights. 

“Is there one universal sign language?”

If only it were that easy. Sign languages evolve naturally within communities, just like spoken languages. There is an International Sign used as a contact/auxiliary system at global events (think conferences and the Deaflympics), but it’s not a full, standardised language like BSL or ASL.

How to mark 23 September (practical steps for organisations)

  1. Plan access, not add-ons. For events, book interpreters early, budget appropriately, and brief speakers. (Conference interpreting in BSL requires preparation materials just like spoken-language interpreting.)

  2. Publish in BSL. Where messages are important or high-impact (policy updates, safety info, HR changes), publish short BSL videos alongside text. The BSL Act expects better government communication — it’s a good model for everyone. (accessibility.blog.gov.uk)

  3. Train your teams. Offer BSL awareness or beginner sessions; build internal champions.

  4. Audit your customer journeys. Check booking processes, help content, and signage; commit to fixes with timelines.

  5. Celebrate Deaf culture. Commission Deaf creatives, share stories responsibly, and credit sources/creators.

  6. Make it ongoing. IDSL is the spark; the real impact is what you change between 24 September and next year.

About Interpreting Matters (and how we can help)

At Interpreting Matters, we provide fully qualified British Sign Language (BSL) interpreters for a wide range of settings — from healthcare and legal appointments to conferences, performances, and workplace events. Whether you need an interpreter on-site or remotely, we match you with professionals who understand not just the language, but the culture and context of each interaction.

Contact us today to book a BSL interpreter