How to Make Videos Accessible in Multiple Languages

Making a video usable across languages and disabilities requires more than uploading a caption file. It requires a five-layer localisation stack — transcript, translated subtitles, dubbed audio, audio description, and sign-language interpretation — produced under ISO 17100 quality control and mapped to WCAG 2.2 clauses that UK and EU regulators enforce.

What are the 5 layers of the multilingual video accessibility stack?

The five layers are a source-language transcript, translated subtitles or SDH, dubbed or voice-over audio tracks, audio description for visual information, and sign-language interpretation — each solving a distinct barrier and mapped to a specific WCAG 2.2 success criterion.

Layer 1 — What is a transcript and why start there?

A transcript is the full plain-text record of a video’s audio and it is the source asset from which every other layer is produced, which is why the workflow starts here. A verbatim transcript also acts as a standalone accessibility asset for deaf-blind users on refreshable braille displays and improves search indexing, because crawlers read text rather than watching video.

Our transcript pack is priced from £30 per page and delivered as a translated document under the same discipline as our Document Translation Services, with the source-language transcript feeding directly into the translation queue for every downstream language.

Layer 2 — How do translated subtitles and SDH differ?

Translated subtitles render spoken dialogue in a second language, while SDH (Subtitles for the Deaf and Hard-of-Hearing) additionally carry speaker labels and non-speech cues such as [door slams] or [music swells]. Standard subtitles assume the viewer hears the audio and only needs a language bridge; SDH assumes the viewer does not hear at all and needs the full acoustic scene rendered in text.

• Translated subtitles: dialogue only, one language other than the audio.
• SDH: dialogue + speaker IDs + sound effects + music cues, in the target language.
• Closed captions: same-language transcription including non-speech audio, toggled on by the viewer.

Layer 3 — When should you dub the audio instead of subtitling?

Dub the audio when the target audience reads slowly, when the video is under 3 minutes and text would obscure the frame, or when platform norms expect a native voice track — children’s content, broadcast TV in France, Germany, Italy, Spain. Dubbing replaces the original voice track with a lip-synced target-language recording; voice-over (UN-style) leaves the original audio audible under a narrated translation.

Layer 4 — What does audio description add for blind viewers?

Audio description is a narrated track inserted between dialogue that describes visual information — actions, settings, on-screen text, and body language — so blind and low-vision viewers receive the same story information as sighted viewers. It sits on a secondary audio channel and slots into the natural pauses in the original mix. WCAG 2.2 clause 1.2.5 requires it at Level AA when significant visual information is not already carried by the dialogue.

Layer 5 — Why is sign-language interpretation a separate deliverable?

Sign-language interpretation is a separate deliverable because BSL, ASL, and other sign languages are full natural languages with their own grammar, not English on hands, and many Deaf viewers use sign as a first language even when they can read captions. British Sign Language has its own word order, spatial grammar, and idiom, and a qualified interpreter is filmed as a picture-in-picture inset (commonly bottom-right) so the sign track runs in parallel with the video.

How do you add audio description for blind and low-vision viewers?

Audio description is a narrated account of the significant visual information in a video — actions, scene changes, on-screen text, and relevant body language — inserted into the natural pauses between dialogue so that blind and low-vision viewers receive the same informational content as sighted audiences. WCAG 2.2 clause 1.2.5 requires audio description at Level AA whenever meaningful visual information is not already conveyed by the spoken audio; a talking-head interview with descriptive narration needs far less AD than a wordless demonstration or an action sequence.

To achieve the highest standard of accessibility, audio description should be commissioned as part of the original production schedule rather than added after the edit is locked, because retrofitting AD into a densely edited sequence often requires cutting additional pauses into the timeline — a process that lengthens delivery and increases cost. A clear, well-lit video showing the speaker’s face also supports viewers who lip-read, making considered production choices a multiplier across multiple accessibility outcomes.

1. Spot the video for description gaps — identify every silent or low-dialogue moment longer than approximately two seconds where visual information is being conveyed.
2. Draft the AD script — describe actions, settings, on-screen text, and body language in concise, objective language without overlapping existing dialogue.
3. Time-code each description line — align every AD cue to the exact frame at which it should enter to avoid clashing with speech.
4. Record with a matched voice artist — select a voice whose tone, pace, and register suit the video’s style; record in a treated studio environment.
5. Deliver the correct stems — provide either a separate AD audio track (extended AD) or a mixed master in which the original audio ducks by 6–10 dB beneath the description, depending on the destination player’s capability.

Sign-language interpretation is a complementary access service: a qualified interpreter is filmed signing the full audio content in BSL, ASL, or another sign language and composited as an on-screen inset, ensuring Deaf viewers who use sign language as their primary language receive the content in the most natural form for them.

Which UK and EU laws require multilingual video accessibility?

Three overlapping regulatory frameworks govern video accessibility for UK and EU audiences, and each framework imposes distinct obligations on different categories of publisher. Understanding which regime applies to your organisation is the essential first step before scoping any multilingual video project.

• Ofcom — UK licensed broadcasters are required to caption up to 80% of qualifying programming, provide audio description on 10%, and carry sign-language interpretation on 5%. These are hard targets against which channel compliance is measured each year. Failure to meet them is a regulatory matter, not merely a best-practice shortfall.
• Public Sector Bodies Accessibility Regulations 2018 (PSBAR) — UK public-sector bodies must ensure their video content meets WCAG 2.2 AA. That standard includes clause 1.2.1 (audio-only and video-only alternatives), clause 1.2.2 (captions at Level A), clause 1.2.3 (audio description or media alternative at Level A), and clause 1.2.5 (audio description at Level AA). A public-sector video published without captions is already in breach of domestic law.
• European Accessibility Act (EAA) — from 28 June 2025, the EAA mandates accessible audiovisual media services for products and services sold into the EU. Organisations that distribute video content commercially in any EU member state must ensure that content meets accessibility requirements as of that date, regardless of where the organisation is headquartered.
• Equality Act 2010 — the reasonable-adjustment duty under this Act covers accessible video for any service offered to the public in Great Britain, giving individuals a potential avenue for challenge where accessibility barriers are not addressed.

ISO 17100 is the international quality standard for translation services and, while not a law, is required by many public procurement frameworks and by regulated industries. It mandates a qualified human translator, an independent reviser, and a formal QA sign-off for every translation — including subtitle and dubbing scripts — which means machine-only outputs do not satisfy ISO 17100 compliance. For regulated content such as compliance training, evidence videos, or public communications, meeting the translation quality standard is as important as meeting the technical accessibility specification.

For regulated content where subtitles and transcripts need to accompany certified documentary evidence — an evidence video paired with a certified transcript, for example — our Legal Translation Services handle the certification requirements in parallel with the accessibility deliverables.

What is a practical checklist for shipping a multilingual, accessible video?

Shipping a multilingual accessible video is a sequenced workflow where each stage depends on the quality of the one before it. The transcript is the source of truth for every downstream deliverable, so a transcription error propagates into subtitles, dubs, and audio description scripts simultaneously — which is why locking an accurate, time-coded transcript before any translation begins is the most important quality gate in the entire process.

1. Lock the source-language master — picture and audio must be final before any translation or timing work begins; changes to the edit after subtitles are timed require full retiming.
2. Transcribe the audio — produce a full plain-text record of all speech, including speaker IDs and non-speech audio cues, time-coded to the frame.
3. Translate the transcript into each target language under ISO 17100 — a qualified translator produces the first draft; an independent reviser reviews it; a QA sign-off completes the cycle before any subtitle timing or voice recording begins.
4. Time subtitles to broadcast reading speeds — target 15–17 characters per second, maximum two lines per card, maximum 42 characters per line; subtitle timing is a specialist skill distinct from translation.
5. Record voice-over or dubbing audio in a treated studio — deliver labelled stems (dialogue, music, effects) to allow post-production flexibility; lip-synced dubbing replaces the original voice track entirely and requires a full voice cast and final mix.
6. Write, time, and record the audio description track — description lines must fit the natural pauses in the original dialogue without overlapping speech; deliver either a separate AD stem or a mixed master.
7. Film the BSL or ASL interpreter and composite as a picture-in-picture inset — the interpreter must be a qualified signer for the specific sign language required; inset size and position must not obscure critical on-screen information.
8. Embed subtitle tracks with correct BCP-47 language codes — use en-GB, es-ES, ar-SA, and equivalent codes so players surface the correct language to the correct viewer automatically.
9. Apply player-level accessibility settings — disable autoplay-with-sound; confirm no content flashes more than three times per second (a WCAG seizure-safety requirement).
10. Test on the accessible player — verify keyboard navigation, caption toggle, screen-reader control announcements, and correct audio-track switching across the destination platforms, including mobile browsers.

Building this checklist into your production schedule before the shoot — rather than treating accessibility as a post-delivery task — keeps every deliverable on the critical path and avoids the cost and delay of retrofitting access assets into a locked edit.