Jim - on your 16 Oct 19 - 06:40 PM you seem to be forgetting the oral tradition of songs being passed on through listening to others.

As I built my repertoire, if the tune was already on Mudcat or elsewhere on the web, I used it (occasionally transposing for my tenor recorder intros) but, if not, I learnt solely from the singing of others (at clubs OR radio, CD, etc.), them mimicked my voice with that recorder or keyboards and wrote it down using a simple ABC notation system - not trusting my memory.