In a previous life, Lucía sang me a few notes of a lullaby, that she remembered her daddy sang to her when she was a kid, to the non-sensical words "Rocky, Sabaki". I hadn't heard such a song before, but I promptly completed those five notes into a complete melody, that to me sounds as a most obvious continuation. Later, she would tell me what her dad had been singing to her really was that lullaby everyone knows and every baby machine annoyingly plays, which I identified as Brahm's lullaby, also known in English as "Lullaby and Goodnight". Therefore, from these misremembered notes, I had made a melody of my own. As I finally have a daughter of my own to sing it to, I wrote words of my own to this melody. And out of the rhymes that I originally rejected from the song, I could not resist writing a second stanza. Note that I often sing "Véra, my Véra" instead of "Rocky, Sabaki". Obviously YMMV.
Update 2014-10-13: Now that I realized that it's easier to learn the guitar than to find a guitarist to accompany me, I've modified the score so it shows actual guitar chords instead of chord names. I can also imagine an accompaniment with a harp, with sixteenth notes that descend the chords; but I'm not likely to ever be able to debug it, so I'll pass trying to write down a necessarily buggy version — though maybe I could recycle it as a piano's left hand part. Hopefully, at some point I'll get good enough at guitar to record a semi-decent interpretation.
Update 2014-11-25: As my fumbling at the guitar improved, I've updated the score to use 4-finger chords instead of 3-finger chords. This way, it's an improved song that I'm failing to play adequately!