Just this week, VV has started making an almost inaudible "ee-hee" sound for "yes," complementing her headshaking for "no" (or, more likely, "hell no, you moron.") I remember when Julia started being able to express both agreement and disagreement, and it's just as wonderful now to be able to count on the kid having both words to use. I was getting tired of inferring "yes" from no headshaking and being proven wrong.
Here is "ee-hee" in action: after her (6:10 a.m.) breakfast, I asked VV is she wanted to read a book. "Ee-hee," she said, tipping out of my arms to head for the bookshelf.
There are 19 books on, under, and around her. Every one of them had at least a few minutes' attention.