If you're posting a video clip or an audio clip attached to a post, remember to include a text description which describes the sound. This is important so that the video or audio is accessible to deaf people.
Also, if it's a video, it's important to describe both the sound and the visuals so that it's accessible to everyone.
Text descriptions for audio and video are added just like text descriptions for images (exact steps vary depending on which app you use).
Yup, just like for blindness accessibility!
Yeah, it gets complicated as some people cannot write alt texts for various reasons (for example a blind person posting an image). Probably best to just have a reminder system, which some servers use, where the post is highlighted in red if there's no alt text: