Closing the gap; the gap that can be as vast as the Grand Canyon, small or non existent. Communicating with one another can be difficult enough; communicating with another species can seem insurmountable. Learning how to communicate best with your dog and understand how they communicate takes some work. Naturally we see things in our human perspective. We take a behavior that we see and make it human or anthropomorphize. It can be very difficult to not see canine behaviors as human and as such interpret them in our human way.
Dogs are very clear cut with their communications; but like us some are better at it than others. Some wear their emotions on their sleeves while others keep them more hidden. This is where experience or simply knowing your dog comes into play. Often I will see a behavior that is quite obvious although an owner may misinterpret it. Before I offer the canine interpretation I ask a lot of questions; is this a normal reaction for this dog? Is this a similar level of reaction for this dog? etc. Then I will enlighten the owner and typically they see much clearer once their human emotion is swept away from muddling up the message.
Dogs deal in black and white; so the clearer you make your communications the better they will understand them. Too much talk, too much movement and things can get lost in translation. This is why many positive trainers opt to use a clicker. The clicker is a clear marker; the clicker sound means "I like this behavior." Timing is essential when marking desirable behaviors; and it is just as important for marking undesirable behaviors. Clear, uncluttered and simple; this is how dogs communicate. Although their messages are quite clear; that does not mean that they are not extremely complicated. Being that there is an exceeding difference between dogs; some are an easy read, some take some work.
Signals can be a clear as day but if you are not watching; you're not going to see them. And if you are only watching for the big ones; you may miss the small messages that can hold a great deal of information within them. Communicating is extremely important for training, interactions and basically day to day life with your dog. Your dog is constantly communicating with you; heck by the time you get out of bed in the morning they've probably informed you of a wealth of information.
Have a look; it is much clearer than you may think. They have a lot to say to us.