Absolutely, Richard.

I would imagine most active singers on the folk scene pick up songs in a variety of ways. There are those that I have deliberately sought out and learnt from books or recordings, and those I have picked up simply by hearing them sung frequently. In some cases I have heard and read many versions of a ballad (usually a Child Ballad) that I have been able to construct a version in my own head without recourse to an existing version. I know traditional singers who have learnt their songs in similar varied ways, so we're not all that different to them in many ways.