At first this happened without us prompting him for the answers. Now he says this all the time. :)
Mommy: "Who's sweet boy are you?"
Eli: "Mommy's sweet boy!!" (followed by lots of laughter)
Daddy: "Who's the man?"
Eli: "Daddy's the man!!"
When we pass the cows on the way to the grocery store...
Mommy: "Eli, say hi to the cows."
Eli: "Hi cows! It's good to see you!"
Mommy: "Are the cows eating?"
Eli: "Yes, eating ice cream!"