From what I can gather, "period wise", mostly chords were used on the harp to accompany voice; use them after the vocal phrase, or just barely before; I have seldom heard anybody actually play the melody at the same time they are singing it.If you are doing a ballad, use minors, and discords to "highlight" the vocal, and "pre-sage" the story. Listen to Ann(e) Heyman......she does REALLY fast stuff on a Welsh triple strung, and some vocals on a double strung..........beyond me. I just sort of fake around the chords if I want to sing, I can't think about that many things at once.