- You can search for comments by modern scholars about it; e.g. search for [witzel "tape recorder"] on the web / in Google Books to find some quotations of a memorable analogy.
- You should find some material online in connection with "The Tradition of Vedic Chanting" being part of UNESCO's "intangible cultural heritage" lists / "Masterpieces of the Oral and Intangible Heritage of Humanity". I believe there were some documentaries produced. haven't looked closely but these sites look related: https://ich.unesco.org/en/RL/tradition-of-vedic-chanting-000... / http://vedicheritage.gov.in/vedic-chanting-unesco/
- There's some good information on the Wikipedia article at https://en.wikipedia.org/w/index.php?title=Vedic_chant&oldid... e.g. for every string of the form "abcd..." one learns not just "abcd..." but also "ab bc cd..." and "abbaab bccbbc cddccd..." and some learn even more dizzying schemes.
- There are some documentaries on these schools, e.g. https://www.youtube.com/watch?v=5FxYydNlrFk (there are a few more longer ones).
Purely from an information-transmission POV this feat is fascinating. Does anyone know where more information can be found about this?