Ballad of the Goddess
The Ballad of the Goddess is first heard at the start of the game. Zelda plays the song on the Goddess's Harp and sings part of the song in Hylian until her Loftwing comes. When Link arrives, Zelda is still singing, but there are subtitles with the lyrics to the first verse. It is revealed that she is practicing the song for the Wing Ceremony, where she sings it once again after placing the Bird Statuette.
Link later learns the song from the old woman in the Sealed Temple on the Goddess's Harp. When he plays it for the first time, the Gate of Time appears. He then must travel back to the sky to speak with Gaepora, who will tech him the lyrics of the second verse. The lyrics are a clue for Link to turn the two windmills on Skyloft toward the Light Tower. Link then plays the song on top of the Light Tower while Fi sings, which creates a beam of light that leads to the Isle of Songs and forms a path inside the Thunderhead.