All platforms, apps, and websites must allow users to customize the screen reader or text-to-speech engine presentation and synthetic voice. Having the option to select more familiar voice settings increases comprehension, comfort, and efficiency for users while also reducing frustration and confusion.
6.2.4-A
Users must have control over the accent, pitch, speed, verbosity, and volume of spoken information.
6.2.4-B
All platforms, apps, and websites should also include user-defined controls for relative volume (how loud the playback volume is when text-to-speech is speaking). These settings should offer the ability to not only turn off playback audio, but also require a minimum of “low, medium, and high” options. Ideally, this would offer a variable percentage between 0-100%.