What does Daddy say?

Dene is a typical 22 month old. Learning words and "talking" constantly. Along with naming and identifying body parts he is picking up on a few animal sounds. One day while changing him I kept him busy by asking him "What does a dog say?" His reply: "woof-woof" (which sounds more like "woo-woo") Then I ask him "What does a cow say?" His reply: "Moo Moo" At this point I ran out of animal sounds I knew he could identify so I ask him "What does Daddy say?" His reply: "No No"