But then Cecil Sharp is not renouned for being a great musician, just as being a collector of anthropological oddities.

A musician with a good ear who can read and write will have better luck.

I don't think there is such a thing as a musical stenographer, but most Jazz musicians learn sooner or later that the most efficient way of getting inside the head of musician they like and working out what he's up to is ti transcribe his work and work out whats going on phrase by phrase.

As with everything, Practise makes perfect.