In researching for the subject of music in Middle-earth, I have covered a wide range of Tolkien's works within a relatively short time. That means I notice similarities that are otherwise not close enough to each other to be connected. So it is with Ulmo and Goldberry. The connecting elements are water and music.
We read in the Sil that the echo of the Music of the Ainur lives on in water, which is Ulmo's particular element. He has (an) instrument(s), the Ulumúri, horns made of shell, which awakens the hearts of Elves and Men to a longing for the sea. He speaks through the music of water - fountains, streams, etc. He taught the Elves, especially the Teleri, music.
Goldberry is titled "River-daughter", an interesting epithet that makes her as much an enigma as her spouse Tom is. She also sings many songs, and they are closely connected with water - rain, especially, as we read of her rain-song and Tom's description of "Goldberry's washing day". She inspires Frodo, who seldom makes songs, to his own in praise of her.
I realize that we have no information of any connection between the two characters, and this could be another futile attempt to explain an enigma, but perhaps we can come up with some interesting ideas of our own. Could there be some connection between the two? What could it be?
Here's a real crackpot theory to start us off - what if "River" stands for Ulmo himself? Then Goldberry would be his daughter!
