Just in case your life wasn't confusing enough already, whoever was in charge of creating the English language invented heteronyms, which are two or more words spelled identically but having different pronunciations and definitions. Heteronyms, if lacking proper context, might make a piece of text, such as a page on a website (*hint* *hint*), unclear or unintelligible.
If the meaning of certain words on your site is dependent on knowing how they're pronounced, you should add a mechanism for users to access those pronunciations. This will prove helpful for those experiencing low or no vision or for those with reading disabilities.
Often if a word has multiple possible pronunciations and definitions, users can understand its meaning through context, but for more sophisticated or ambiguous sentences that may prove a more difficult task. In addition, screen readers may use the incorrect pronunciation when going through your page.
There are a few ways you can provide more clarity to users when they come across words with uncertain pronunciations and definitions. For instance, you can link words to sound files that give the intended pronunciations. You can also link words to a glossary, where you can then provide additional information on the word's meaning and pronunciation.
This rule has been designated AAA.
For more information on WCAG conformance levels, check out our post on <conformance>.