Amazingly enough, in the video below, she actually demonstrates three of her favorite sounds. The first is a growl, which she got stuck on about 2 months ago, the third is the raspberry that she was stuck on between 5 and 8 months old, and the second/middle sound you'll hear just briefly is something that she only discovered last week...it has become her new favorite, taking about 90% of every sound that comes out of her mouth. I actually witnessed her discover this new guttural sound, and I'd tell you how she came about it, but it's a bit disgusting (it's related to her cold).
She tends to only growl these days when she's conversing with her old friend Monkey, or when she's frustrated at something and pretends she's The Incredible Hulk. The raspberry (which was superbly displayed in this video, I might add) has become a rare treat.