And I got to know about this when I read about the dog above, Horus. It is deaf and was mistreated by its previous owners - a couple of heroin addicts -, which caused it to become extremely disobedient and restless. After spending more than 18 months in animal shelters, Rosie Gibs, an enthusiast of the sign language who helps the Deaf Dog Network (a network that helps deaf dogs), found it. She teached Horus how to use the sign language and nowadays it mastered more than 50 commands and won gold, silver and bronze medals from the Kennel Club Good Citizen.
~Ally