He's barking that much he could be an overly demanding little guy who has learned that barking gets him attention . Their are behavioral technuqies that help in resolving this issue . He needs to be taught that he does not have to bark to get everybody's attention. I've seen Victoria Stilwell train a young pom who was a constant barker. It takes patience, however this can be achieved.
Try to ignore the barking. Do not give him what he wants , until he quits barking, then reward him after he stops the yapping.
My Suzi barks when she wants something really badly too. If someone picks up your dog, or pets him when he barks this only reinforces the barking behavior. He needs to be totally ingnored , and then rewarded for not barking. He will soon learn . Yorkies are very smart dogs.