The Duck Says Quack (or is it cack)

N is not a big talker yet, but it's starting. Last week, he said the name of his primary caregiver at daycare, and also the name of one of the little girls. Yesterday he started making animal sounds. Caught me by surprise. I've been asking him for a while now with no answer, but then yesterday, when I said "what does the duck say?" he said "cack cack cack". Oh and his cows say "oooooo".