A11y: What are Text Alternatives?
All non-text content that is presented to the user has a text alternative that serves the equivalent purpose. In other words, any visual-based media needs to have a text explanation of what it is. This includes photographs, charts, animations, graphs, sound clips, and video.
Providing text alternatives allows for content to be accessed by multiple users in multiple ways. For example, someone who is blind can have an image’s alternative text read to them, and someone who is deaf can read a video or audio transcript.