A few months ago, my son Jack started calling me "daddy" instead of "dada." Speech development and all that jazz. He's almost three so he's pretty much a nonstop chatterbox and his pronunciation gets clearer every day.
A couple of weeks ago, out of the blue, he started calling me "Big Daddy" instead of just daddy. "Big Daddy, come play with my trains." or "Big Daddy, can I have a juicebox?" Things like that.
I don't know where he came up with Big Daddy but I've got to say, it's pretty much my favorite name ever. It literally cracks me up everytime he says it.