Who is singing, and who is the "well beloved" (5:1)?

The chapter doesn't name the singer. The last heading before it, at 2:1, says, "This is what Isaiah the son of Amoz saw concerning Judah and Jerusalem" (2:1), and in the chapter someone says, "In my ears, the LORD of Armies says" (5:9); the song itself names no singer. He sings "for my well beloved" about "his vineyard" (5:1). From 5:3 the owner speaks for himself, as I: "please judge between me and my vineyard" (5:3). And 5:7 says whose vineyard it is: "For the vineyard of the LORD of Armies is the house of Israel" (5:7). So the vineyard the singer's beloved had (5:1) is the vineyard of the LORD of Armies (5:7). In Hebrew the verse has two words the WEB gives as beloved: yedid, in "my well beloved" and "My beloved had a vineyard", and dod, in "a song of my beloved" (tap well beloved). The chapter says nothing more about the singer, and these notes don't either.