However, she produces "the noise". I'd put in on par with Payne's "the face" in its ability to be simultaneously cute and terrifying. She does it when she's excited, curious, happy, or feeling social. So, I hear it a lot.
It's done in a whisper, and goes "saaaaah. aaaaaah." slowly, and with a sort of hair raising methodic...ness.
I guess now wouldn't be the best time to ask for babysitting volunteers?