Thanks for reaching out! Currently there is not a function in TALENT that allows for changing the playback speed of videos. If there are Time Synched comments on a video, you can click on the comment, and the video player will jump to that point in the video.
I'm happy to share your interest about having additional video player controls within TALENT. Please continue to share your feedback and feature requests, and if there are more questions that come up, we're happy to help!