In my experience people rarely need that sort of encouragement - just a few songs and a few pints and off they go. Folk is about people singing in their natural voices & some are better at it than others. The best way to learn though is by doing it AND listening to archive recordings of Traditional Singers. Whatever, there exists a fine diversity of singers, untrained and unique though occasionally you might run into a Trained Folk Singer and it's pretty obvious where they're coming from. I find this a lot with ballad singers, which is becoming very formalised. Go listen to Mrs Pearl Brewer on the Max Hunter archive (she's under M for Mrs!) - her Lord Thomas is damn near definitive, though maybe a little vivid for over-precious revival sensibilities. Her Cruel Mother (Greenwood Side) is second to none.

Folk Singing & Ballad singing was the soapy vernacular - it's certainly Not storytelling, though it rides on a similar corporeal vibe. In the revival there's various strands of vocal interpretation & affectation going on, from Jack Langstaff to The Unthanks (both of whom I love very dearly) but to hear this stuff in its natural habitat is a very different thing altogether. I think that's the beauty of singarounds - it's as close to the natural habitat as we can get these days.