What is an ADT?
An introduction to Accessible Digital Textbooks — what makes them different from a PDF, and what they can include.
An Accessible Digital Textbook — or ADT — is a structured, interactive version of a book designed to work for all learners, including those with visual, auditory, cognitive, or motor disabilities.
An ADT is not a PDF made slightly more readable. It is a different kind of object: structured content that can be navigated by section, listened to through narration, read in multiple languages, explored through a glossary, and used by assistive technologies in the way they were designed to work.
A well-produced ADT may include:
- Structured text, organized by heading, section, and paragraph
- Audio narration in one or more languages, with optional word-by-word highlighting as it plays
- Image descriptions that explain what an image shows
- Comprehension quizzes and interactive activities
- A glossary of key terms
- A table of contents for navigation
- Sign language video integrated alongside the text
- Translations into other languages, including in-image text for figures that need it
- Easy-read adaptations for learners who need simpler language
Not every ADT needs all of these. What makes it an ADT is that the content is structured, accessible, and not locked inside a static file.
Once an ADT is produced and validated, it can be preloaded on tablets or other devices and used in low-bandwidth or offline environments — which matters significantly in the contexts where it is most needed.
ADTs are at the center of UNICEF's Accessible Textbooks for All initiative, which supports ministries of education around the world in converting textbooks into accessible digital formats at scale.