From the previous stanza, we're left with the start of a sentence – "The window square" – but we don't know what it means until now.
This poem builds itself up as a collection of images – from watches ticking to statues standing to cats yawning. These lines follow in this trend even as they situate us in time.
Here's what we mean: have you ever gotten up early – really, really early? Early enough to see the sky brighten and all of the fading night stars disappear? Well, that's where our speaker is now – looking out the window and watching day begin. It's a new start. A new beginning. And probably a new baby's first day at home. That's big stuff, folks.
Notice how the introduction of temporality (the coming of day) situates our speaker in a concrete location. She's not thinking any more about her role as a mother or the child's place in the universe. She's just standing in her baby's room, watching the outside world slowly change.
We're not totally sure about this, but there seems to be a shift in the emotional currents of this poem, as well. All of a sudden that bright, busy world is nothing more than "dull" stars. All the action is taking place inside – where the baby is.
[…] And now you try Your handful of notes; The clear vowels rise like balloons.
Notice how we're still living in the moment? It's like the entire poem has been gearing up for two little words, "and now."
Why is that so important? Well, if this entire poem has been a "song" addressed to a baby, then this is the point where it comes full circle. See, our speaker has been "singing" (or, well, talking) to her infant. And now the infant sings back, trying out "notes" that become "vowels." A mother's language is matched by baby language – and communication is born. We've got lots more to say about this, believe us. Check out our thoughts on the title for more.
(We have to admit, we think our speaker's just a little bit optimistic here. After all, most baby sounds that we've heard are just sounds. They're not necessarily identifiable as "vowels." But hey, poets and new moms get to have a little poetic license, don't they?)
Plath seems to date the birth of the mother-infant bond from the first moment of communication – the first time that the baby makes an attempt to express itself to its mother. Awww. That's pretty sweet, huh?
Well, we don't want to get maudlin here. Plath would probably be the first person to mock us for too much sentimentality. But dating the birth of a relationship from the start of communication is a pretty incredible act, and that's what our speaker has allowed herself to do.