# Sign language (/docs/enhance/sign-language)
For many deaf learners, sign language is their first language — and written text is a second one. Sign language videos embedded alongside the content make an ADT genuinely accessible to these learners, rather than only technically readable.
ADTs produced with the initiative have included sign language in national sign languages (for example ASL and LIBRAS in existing ADTs).
## Decisions to make [#decisions-to-make]
* **Which sign language?** Sign languages are not universal — each country (sometimes each region) has its own. The right choice depends on where the ADT will be used.
* **What is the source of the videos?** Sign language content requires human signers and video production — it is not generated automatically by the tool. Each video is filmed against **one Storyboard section** — the same sections used throughout the rest of the book — so a full sign language pass means producing one video per section, not a single video for the whole book. This stage is for organizing videos you already have, not producing them.
Because each video maps to one Storyboard section, sign language production should normally start only once the book's content and section flow are finalized and approved — going back to re-record videos after a section changes or gets restructured is costly. Treat Sign Language as one of the last stages you run, not an early one.
## Uploading and assigning videos [#uploading-and-assigning-videos]
Sign Language needs your book's sections built first — if [Storyboard](/docs/convert-pdf/storyboard) isn't finished yet, the stage tells you so instead of letting you run it. Once it's ready, open the **Sign Language** stage: there's no AI step to run here, just videos to upload and match to sections, one at a time.
* **Add videos** to upload one or more `.mp4`/`.webm` files. Uploaded videos start out **unassigned** until you match them to a section.
* **Assign** each video to a Storyboard section from a dropdown — one video per section. A **Coverage** bar shows how many of the book's sections have a video, and a **Next missing section** shortcut jumps straight to the next gap.
* **Manage all sections** opens a full list of every section, so you can review or reassign videos beyond the one-at-a-time flow.
The reader shows the matching video in a small player as the user scrolls through the page.
Sign Language doesn't run or regenerate anything — it's pure asset management. There's nothing to rerun when upstream content changes; if a section's text changes meaningfully, revisit whether its video still matches.