In 1931 Mr. and Mrs. Irving began to hear strange noises behind the walls. There were taps. hisses. growls. squeaks, and other animal sounds Then one day Mr. Irving heard a gurgle. It sounded like a baby learning to talk. Mr. Irving thought he would answer the sounds. He barked ike a dog. He meowed like cat. To his surprise. his a sounds were repeated a shrill. high voice in Mr. Irving made the sounds again. This time he followed each one with the name of the animal he was imitating. The voice behind the wall repeated every word he said