Because I am nothing if not thorough, I listened to “Shilric and Vinvela,” D293. Here are Roman Trekel and Ruth Ziesak singing it:
What goes on in this song is as follows. Vinvela describes her lover, Shilric, who is a ‘son of the hills’ and a skilled hunter. She says that she will behold him unseen from a high rock, just as she first caught sight of him – the best looking among all his friends. Shilric hears this ‘voice like a summer wind’ and laments that he has left and sees her no more. ‘Then thou art gone!’ Vinvela replies. ‘I am alone on the hill.’ Shilric asks Vinvela to remember him and raise him a tomb. (It is as confusing as it sounds. Possibly the conventions of being in one place and not in another operated differently in the misty Gaelic past.) Vinvela promises that she will. They both seem certain that Shilric will die.
As we know, Vinvela ultimately gets the jump on Shilric as far as dying goes. But leave that aside for now. I am still figuring out what if anything I think about this song, and I think the way to go about this is to describe it.
It is in the form of a dialogue. This is a conversation, not a duet, which is significant. It is a series of little recits and mini-arias. Shilric and Vinvela’s voices never touch one another. Schubert could have written this so that the lines of the two speakers overlay one another, but he didn’t. Shilric and Vinvela might well be already apart, as the text suggests. In addition, there is often (if I am hearing this right) a key change when the text changes speakers, e.g. at 3.30 and 6.30. Musically as well as dramatically, the doomed lovers are in different places. These two are communicating with one another, just not in a way that allows them to be in the same place at the same time.
I suppose the argument, then, is that fate’s decree that poor Shilric and Vinvela will never experience a real duet (so to speak) is built into Schubert’s music. Whether this makes you care about Shilric and Vinvela or not is a separate question.