for audio annotation, is there away to have the buttons to slow down or speed up the audio. I want to add such options, so that when there is unclear clip, I can slow it down
Welcome to the forum @Bodor 
Prodigy exposes theWavesurfer instance via window.wavesurfer so you can customize the playback by adding your own HTML and javascript code.
The example in our docs does exactly what you ask for (I think)?
Also here more on injecting custom front-end code.
amazing! it's exactly what I need
thank you