There are three songs in rotation in our house: Pat-a-Cake, Ring Around the Rosy, and Twinkle Twinkle Little Star. We sing others but these are the ones Carter likes to join in on.
For Pat-a-Cake, he does the clapping part, and then he loves to roll his hands while saying "yule" which is "roll" roughly translated. And to mark it with a "C" he points to his belly.
Ring Around the Rosy starts off normal. He sort of runs around in a version of a circle and then after the first two lines says, "Ash ash" and then likes to yell the "DOWN" part. Sometimes he'll fall, sometimes he won't. I have this on video, but haven't gotten around to uploading it yet.
To me, Twinkle Twinkle is the most impressive. He makes a "k" sound repeatedly with his hands in the air opening and closing for the "twinkle twinkle little star" parts (his sitter does up high jazz hands and that's his interpretation of it). And then he'll say the first part of each line. For instance, when it's time for "Up above the world so high" he'll say "up-ah" and for "How I wonder what you are" he says "how."
And I swear the other day he said "ABC" when I asked him if he wanted to sing the ABC song.
This morning he was in his car seat saying "Ash...ash...DOWN" over and over again. And then I saw his little hands in my rear view mirror doing his twinkle fingers.