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Perceivable WCAG 1.2.6

1.2.6 Sign Language (Prerecorded)

Sign language interpretation must be provided for all prerecorded audio content in synchronized media, offering an alternative for users whose primary language is sign language.

Level AAA Moderate WCAG 2.0 (new) WCAG 2.1 WCAG 2.2

What this rule means

WCAG 1.2.6 requires that prerecorded synchronized media include a sign language interpretation of the audio content. This is a Level AAA criterion that goes beyond captions by providing communication in the native language of many deaf individuals. While captions represent audio as written text, sign language conveys meaning through visual-gestural communication with its own grammar and syntax.

The sign language interpretation can be embedded as a picture-in-picture overlay within the video or provided as a separate synchronized video.

Why it matters

For many people who are deaf from birth or early childhood, sign language is their first and most fluent language. Written text — even in the form of captions — represents a second language that may be more difficult to process. Sign language interpretation provides content in their most accessible communication form.

This is particularly important for complex content such as educational materials, legal proceedings, medical information, and government communications where comprehension is critical.

Captions are essential, but they do not replace the need for sign language. For many deaf individuals, sign language is their primary mode of communication and comprehension.

Related axe-core rules

No axe-core rules test for sign language interpretation. This is entirely a manual testing criterion that requires human evaluation to verify the presence and quality of sign language content.

How to test

  1. Identify all prerecorded videos with audio content on the page.
  2. Check whether a sign language interpretation is available — either embedded in the video or as a separate synchronized option.
  3. Have a sign language user evaluate whether the interpretation accurately conveys the audio content.
  4. Verify the sign language interpreter is clearly visible with adequate lighting, contrast, and resolution.
  5. Confirm the interpretation is synchronized with the audio and covers all spoken content.

How to fix

Embed a sign language interpretation window within the video:

<video controls>
  <source src="/presentation-with-signer.mp4" type="video/mp4" />
  <track kind="captions" src="/presentation.vtt" srclang="en" label="English" default />
</video>

<!-- Or provide as a separate synchronized video -->
<div class="media-container" style="display: flex; gap: 1rem;">
  <video id="main-video" controls style="flex: 3;">
    <source src="/presentation.mp4" type="video/mp4" />
  </video>
  <video id="sign-video" style="flex: 1;" aria-label="Sign language interpretation">
    <source src="/presentation-sign.mp4" type="video/mp4" />
  </video>
</div>

Synchronize both videos programmatically:

const main = document.getElementById("main-video");
const sign = document.getElementById("sign-video");

main.addEventListener("play", () => {
  sign.currentTime = main.currentTime;
  sign.play();
});

main.addEventListener("pause", () => sign.pause());
main.addEventListener("seeked", () => {
  sign.currentTime = main.currentTime;
});

Common mistakes

  • Using a sign language window that is too small for the interpreter to be clearly seen.
  • Poor lighting or low contrast behind the interpreter, making signs difficult to distinguish.
  • Using a sign language interpreter who is not fluent in the specific sign language of the target audience (e.g., using ASL for a BSL audience).
  • Not synchronizing the sign language video with the main video, causing timing mismatches.
  • Placing the interpreter window over important visual content in the main video.

Resources