The words are a lullaby to a little one who doesn't know yet that the life it is born into is difficult, so the mom is trying to pretend that everything is okay, wanting something different for her child than what is expected.
In this version, Janis Joplin expresses a deep yearning layered with grief in the song, even though her vocalizations are difficult to listen to, I can't help but feel that the emotions are genuine. I also relate to the fact that the sounds that Joplin is making convey more than what the lyrics all by themselves ever could. I wish people could appreciate the art in this, instead of just writing it all off as just another rock and roll song. Art isn't always pretty, but it can have a beauty that transcends our lives even through it's ugliness.
It reminds of me of the verse about prayer when the Holy Spirit interprets for us to God what groanings we have in our hearts that are too deep for words. This amazes me, it absolutely amazes me that God wants to know, hear and understand intimately what our hearts are feeling. Yes, when we worship, it is nice when we all harmonize and sound...nice. But I can't help but to think that God wants more than that from us.
If I were a brave woman, I would pray like Janis Joplin sings.