I'm with our unnamed Guest above to an extent, in so far as the lyrics to a song are not necessarily poems (and vice versa). Surely, a song lyric is fifty per cent of a song, i.e. a musical form; a poem is a work of literature, intended to be read or recited, but not necessarily sung?

Tolkien's 'songs' in the books were meant to have been sung - in the books. However, once he put them out there, people are free to attempt setting them to tunes 'irrespective of whether or not [Tolkien] wrote them'.

I think most people on Mudcat would probably agree that an orchestra or piano are not going to work very well, and that a harp, lyre or other metal-strung instrument, playing an appropriate traditional or trad-style tune would work best. Having said that, I think they're probably best left alone ...