Give the pronunciation right after ambiguous words
In some writing, how a word sounds is what decides what it means. G120 asks you to put the pronunciation directly after the word, at least the first time it appears on the page. W3C adds a limit that matters. Where the same spelling has more than one pronunciation on the same page, doing it once is not enough and each instance needs its own. W3C lists this as a sufficient technique for 3.1.6 Pronunciation, a Level AAA rule, and we file it with the 3.1 reading and language family because meaning is what it protects. This is not an every-site technique. It earns its place on language teaching material, on documents that turn on proper names, and in writing systems where the written form is ambiguous without the marks that show how to say it.
How we find it in an audit
Our reviewers handle this by hand, because pronunciation only matters where meaning rides on it. We look at proper names, at multilingual passages, at teaching material, and at any word a text-to-speech engine will predictably say wrong in a way that changes the sentence. Where a page has none of that, the technique simply does not come up.
How affected users experience it
Text-to-speech guesses at any word it has no rule for. A wrong guess on a name or a homograph quietly changes the sentence for the listener, with nothing to signal that it happened. Readers with dyslexia and people learning the language hit the same ambiguity in print rather than in sound. A short phonetic spelling after the word settles it for all of them at once.
Passes vs. fails
Passes
The first mention reads 'Cairo (pronounced KAY-roh), Illinois', so the pronunciation travels with the word.
Fails
An article about regional place names writes 'Cairo, Illinois' with nothing to say it is not pronounced like the Egyptian city.
Other ways to satisfy this rule
5 guides on this site are filed under 3.1.6 Pronunciation. 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 G120: Providing the pronunciation immediately following the word. 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.