WebVTT supports displaying captions with timings that display one word at a time, which YouTube auto-generated subtitles use:

00:00:02.159 --> 00:00:03.350 align:start position:0%
okay so i received this exciting email
which<00:00:02.399><c> reads</c><00:00:02.879><c> hello</c>

Plyr doesn't support this, instead doing this:

Here's an example from this video.
What Plyr does now is sort of hard to read