In the "aural" tradition, muscle memory

The way to learn a folk tune or Celtic tune "by ear", in the "aural" tradition, is to disect the tune, phrase by phrase, or, half-phrase. Listen to it, over and over until you can hum it. I keep stopping the Cd after a phrase, and repeat just that part until I can hum it, then move on to the next phrase. Then work out how to play, phrase by phrase, playing over and over several times. Gradually put the phrases together, 1st 2 phrases, then next 2, moving on till you can string together all phases from beginning to end. Your muscle memory, your brain and fingers, will memorize how it "feels" to play each phrase. Muscle memory will keep you playing with ease.