Idea I haven't the skills to create.

Maybe it already exists, I didn't even look. There should be some sort of browser plugin that reads the audio of a file I'm listening to or watching, and when I pause said video or audio/video file, this plugin will back the file up to the beginning of the in-progress sentence.

I stop and start podcasts and youtube videos often because I have the attention span of a gnat, and frequently return to them, without clear memory of just what was being said when I left off. So I get the sound of someone picking up mid-word and have to spend a few seconds trying to remember how it fit in with what I remember of what was being said.