I'm sure every child achieves this milestone at a different time, but one of the happiest parts of my days right now is that Hadley and Leila have started singing. Tony and I sing all the time, and they watch movies with songs in them, so they've picked up a lot of songs, but right now all they really like to sing by themselves is "Twinkle, Twinkle Little Star".
The problem with this age is that the girls understand the concept of the camera and run around to my side of the camera as soon as they see it, to see the pictures. So it's really hard to catch them in a moment where they're willing to be the subjects. That's why this video was taken on my camera phone, and it's the best I've gotten so far.
(Two side notes: please ignore the missing buckle on Hadley's seat. And if you're willing to come help us look for it, we'd be grateful. :) Also, yes, Hadley is teething, as you can see by her chewing on her strap.)
On a related note, can anybody tell me when you can tell if your child will be able to carry a tune? Right now it's not looking so good. :) But it's a joyful noise anyway!