Offer a spoken version of the text
A recording of the page, read aloud, linked from the page itself. G79 is that technique, and W3C files it as sufficient for its reading-level rule, which is Level AAA and concerns content demanding more reading ability than most adults have. It reaches a group that often has no assistive technology at all. Somebody who struggles to decode written words may never have installed a screen reader, because they are not blind and nothing ever pointed them at one. A play button on your page finds them where a technical fix would not. Human narration and synthetic speech both count. The practical question is how often the text changes, because a recording of a page that changes weekly goes stale weekly.
How we find it in an audit
Where a spoken version exists, we check three things. That it covers the whole text rather than the opening, that it is linked from the page it belongs to rather than parked in a media library, and that it matches the copy now rather than an earlier draft. Dense pages carrying legal or medical content get the most attention, since those are where reading level and consequences meet. Where no spoken version exists we record it as an opportunity rather than a defect, because this rule sits above the level most owners are working to.
How affected users experience it
This one is not mainly about blindness, and saying so clears up a lot of confusion. It serves readers with dyslexia, readers with intellectual disabilities, people reading in a second language, and anybody who takes in speech more easily than print. Hearing the words while seeing them is the combination that helps most, which is why a spoken version beside the text beats a spoken version instead of it. Blind readers already have speech of their own and rarely need yours.
Passes vs. fails
Passes
Listen to this page, four minutes, sits above the text, and the recording gets remade whenever the copy changes.
Fails
A benefits explanation exists only as 2,000 words of dense text, with no audio and no summary.
Other ways to satisfy this rule
5 guides on this site are filed under 3.1.5 Reading Level. W3C lists this one as sufficient for that rule on its own. Implement it correctly, in a way your readers' software actually supports, and the rule is met.
This guide is our interpretation of W3C technique G79: Providing a spoken version of the text. W3C publishes its techniques as guidance rather than as the standard, and says so on every one of them. The success criterion is what conformance is measured against, and a technique is one documented way to meet it.