At age 20, while staying with his grandparents in London, Bell set about testing this technique with the help of a beloved friend who had never spoken a word in his life -- his dog, a rescued stray terrier named Trouve.
Because a sustained sound, not a quick bark, would be required to produce speech, Bell's first task was to teach Trouve to start and stop growling on command, which he did by rewarding the animal with treats, writes Bryan Cummins in his book Our Dept To The Dog.
Next, he taught his to sit patiently while making the growl so that Bell could touch his muzzle. Using the training from his father's method, he knew just how to shape Trouve's mouth to produce the sounds "ma, ma, ma." In time, and after many more treats, Bell's dog was able to pronounce "Mama" in a human-like way.
Through reward and repetition, Bell added new syllables to Trouve's vocabulary. With the help of his master gently moving his mouth and chin, soon Trouve was pronouncing "ga", "ah", "ow", and "oo." Arranging these sounds in another order, "ow ah oo, ga, ma-ma," Bell had successfully taught his dog to convincingly articulate the greeting "How are you, Grandmama?"