There're transcripts and/or summaries available for some videos.
You can find links to them either next to the video itself, or on a special Transcripts & summaries page, or in some cases there is just a link to a page that contains both video and associated text.
Cardano whiteboard; overview with Charles Hoskinson
Cardano whiteboard: development with Duncan Coutts
Cardano whiteboard: Kaleidoscope with Dr. Bernardo David
Cardano whiteboard: Sidechains with Dionysis Zindros
Cardano whiteboard; Treasuries, with Bingsheng Zhang, Ph.D. Lecturer