When I picked Lulu up just now and we were walking out of the building, there was a lot of waving bye-bye and chin patting (Lulu's version of ASL "thank you"). Not from other children or parents. Sure several people told us goodbye, but for the most part, it was Lulu. Acknowledging her people? "Goodbye. Goodbye. Thank you. Goodbye. Thank you. Thank you. Goodbye."
Then, when we got in the car and I gave her the sucky (pacifier, pacie, binky, nuknuk, you know) I had brought for her, she thanked ME. Totally on her own, unprompted. It was cool.