Some words are spelled the same but have different meanings and pronunciation. The pronunciation is what may allow the reader to understand which meaning is intended. This occurs in East Asian languages, Hebrew, Arabic, English and other Western European languages.
Sometimes, the context of a sentence or phrase is not enough to work out how a word should be pronounced. When a screen reader comes across such a word, it may mispronounce the word and prevent the user from getting the right meaning.
Note: it does not matter that the text content wasn't written for the purpose of being read aloud — the fact is it will be read aloud to people by screen readers.
A mechanism is available for identifying specific pronunciation of words where meaning of the words, in context, is ambiguous without knowing the pronunciation. (Level AAA)
It thus becomes part of the job of the content writer, editor or manager to ensure that the needs of the screen reader — and thereby the needs of the screen reader user — are met by providing guidance on how certain words should be pronounced.
The distinctly positive aspect to this is that by resolving any confusion about pronunciation for screen readers, you are almost certainly resolving similar confusion in the perceptions of many of your content users, whether they have a disability or not. As is often the case, enhancing accessibility means improving usability.