[sparklite2]

“Another thing is that sung poetry is a very common way to remember and pass on knowledge in a illiterate society.”

Yes it was an essential element.

[seowulf]

“Another thing is that sung poetry is a very common way to remember and pass on knowledge in a illiterate society.”

Yes it was an essential element.

The "rhythm trance" that was mentioned also focuses the mind so that it is easier to remember the words.

Everyone still remembers the alphabet song they learned in kindergarten.