In 1931 Mr. and Mrs. Irving began to were taps, hisses , growls , squeaks, and other animal sounds. Then one they Mr.Irving heard a gurgle. It sound like a baby learning to talk. Mr Irving thought he would answer the sound. he barked like a dog. he meowed like a cat. to his surprise , his sound were repeated in a shrill. high voice. Mr.Irving made the sound 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.