When Nels was one and a half years old, we spent a lot of time teaching him things. We could point to a photo or drawing of an animal such as a horse and ask, "What does the horse say?" and he would reply, "Neigh". He could do this for any animal that has been assigned an official noise. This was not exceptional.
Willem at one and a half answers the question, "What does the cow say?" correctly. Unfortunately, a moo is his response to ANY question phrased in this manner. When one doesn't ask the question, he reverts to his default animal noise, which is "RAAAHR!" He has a foam puzzle book of barnyard animals and I have been chased through the house by foam pigs, sheep, and ducks, all of whom viciously roar "RAAAHR! RAAARGH!" Today the lesson I am trying to convey to Willem is Do Not Use a Pair of Plastic Needlenose Pliers to Smack the Heads of Everyone Who Comes Near to You. I am having middling success.