"At the End of My Leash" is a Canadian show - so there may not be very many people here that watch it, as a majority of the members here are from the US, and may not recieve channels that broadcast it.
Brad's idea behind not speaking to the dog, I believe, is two-fold: First, it makes the human think about what they're doing with the dog; it gets them involved in the animals behaviour - how easy is it to just yell across the room to your dog to "STOP!". By not talking to the dog, the human actually has to get off their butt, walk across the room, and re-direct the dog from the action that is not desired. Second, it actually does make the dog start paying more attention to it's owner. Dogs in the wild (wolves, etc) don't speak to each other. They follow body language. Once a human has established the alpha role, and doesn't speak to the dog, the dog will start paying more attention to the human.
This is what I've gathered from watching the show anyway - there's also a website related to the show, but I'd be breaking the TOS by posting a link...
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