When even relatively happy, well-supported people become the primary caretaker of a very small person, they tend to find themselves eddied out from the world of adults. They are never alone — there is always that tiny person — and yet they are often lonely. Old songs let us feel the fellowship of these other people, across space and time, also holding babies in dark rooms. In 1928, when Lorca gave a lecture in Madrid about the Spanish lullabies he had for years been collecting, he spoke of a woman he had heard singing a sad lullaby, saying that ‘‘a living tradition worked in her, and she faithfully executed its commands, as though listening to the ancient, imperious voices echoing in her blood.’’ After hearing her sing, he said, he ‘‘tried to collect lullabies from every corner of Spain; wishing to know how my countrywomen lull their children to sleep, and after a while I gained the impression that Spain utilizes its saddest melodies and most melancholy texts to tinge her children’s first slumber.’’ He also noted that the woman he heard singing the sad song, upon approach, looked happy.Rivka Galchen, "The Melancholy Mystery of Lullabies." NYT October 14, 2015. It's a great read: Hitchcock, 5,000 year-old Babylonian songs, and the Lullaby Project.