Best Practices for implementing Read Aloud (TTS) in Reading Applications

With the advent of the European Accessibility Act in June 2025, support for read aloud is becoming a mandatory feature for all reading applications.

This repository is meant to document best practices for developers or for anyone interested in understanding the inner-workings of a read aloud feature. It won't target a specific platform, ideally making it suitable for both native and Web apps.

Through a dedicated Github Project, this project also aims to identify issues that get in the way of implementing a good read aloud experience on various platforms.

Overview

If you'd like to understand how Read Aloud works in reading applications, I've recorded a Webinar for the Book Industry Communication (BIC) on May 1st 2025 that covers this in full. The recording is available on YouTube along with the slides on Google Slides.

Steps involved

1. Extracting content from the resources of a publication
2. Breaking down or grouping elements together to generate a list of utterances
3. Pre-processing utterances to improve their readability
4. Voice selection
5. Managing playback and navigation
6. Highlighting the current utterance