Kiddo has now mastered her third sign: "please." She actually learned it very quickly. My husband taught it to her once, then when I brought up the concept a few days later she quickly rubbed her chest (which is the baby equivalent of the sign). So now we request that she says please when we give her things. We are hoping that this will soon replace the insistent "eh, eh, eh" that she does currently.
Yesterday she wanted part of my granola bar, and was pointing and exclaiming her desire. I asked "what do we say?" then quickly realized that while she can sign please, she still doesn't understand when to apply it. So I started explaining to her, "when we want something we don't scream, we say..." At this point Kiddo smiled with understanding and said "AAAHHH!" (her fake scream).
She's so smart. She knew I was looking for a specific action from her, so when she heard scream she knew just what to do.
Laughing, I said, "no, we say please" and then she also quickly rubbed her chest, and I handed over the granola piece. So, she doesn't understand everything I say, but apparently she understands a lot.