From yaps to howls: how to interpret your dog’s bark — and how to get them to tone it down

What exactly is a barking dog trying to achieve? Is it possible to 'translate' their barks and come up with practical solutions to excessive barking?
The interview begins in uneasy silence, as we stare across at each other from our comfy armchairs. It is not exactly Frost/Nixon, because he is a dog. Being up on the furniture should be a treat for him, but we lost that battle long ago.
I repeat my question again: “Why do you bark so much?”