After returning to my large repertoire of songs I've come to the opinion that the secret of 'learning' a song is to absorb the individual function or statement of each individual song in the first place
Words are merely vehicles to carry a story, opinion or emotion set in verse form with a tune added.
I learned a long time ago that the best way for me to retain a song was to recite it using natural speech patterns
Once you make the interpretation of the song emotionally your own, the song becomes fixed - I have managed to revive over two hundred songs I had not sung for decades with very little effort and my retentive memory has never been great
There are no "correct" versions of traditional songs anyway - they are all individual re-interpretations to one degree or another
Jim Carroll