Emoji have become a common way of communicating content to the end user. To a person using a screenreader, however, he/she may not be aware that this content is there at all. By wrapping the emoji in a <span>, giving it the role="img", and providing a useful description in aria-label, the screenreader will treat the emoji as an image in the accessibility tree with an accessible name for the end user.
This rule takes no arguments.
<span role="img" aria-label="Snowman">☃</span> <span role="img" aria-label="Panda">🐼</span> <span role="img" aria-labelledby="panda1">🐼</span>
<span>🐼</span> <i role="img" aria-label="Panda">🐼</i>