Dog communication comes in a variety of forms, and is part of the foundation of dog social behavior. Dogs use certain movements of their bodies and body parts and different vocalizations to send signals. There are a number of basic ways a dog can communicate. These are movements of the ears, eyes, eyebrows, mouth, head, tail, and entire body, as well as barks,growls, whines and whimpers, and howls.
Dogs show emotion with every part of their bodies. These signals are often subtle, but by developing good observational skills we can gain valuable insight into what a dog might be feeling. Sometimes you will need to look at clues from more than one body part and also consider context clues from the environment to figure out how the dog might be feeling. Most people know the signs of a happy tail wagging dog, but often the tail does not give the only clues. You need to look at the whole dog and the environmental context to get the whole picture.
Part of communication, especially with another species, is to know how to communicate based on the social system the animal instinctively understands. For dogs, learning about the 'pack system' and how it affects everything a dog does in life, is the foundation of your relationship with your dog. If you went to live in a country that spoke another language the chances are you would try and learn that language so you could live and ask for what you wanted. You would also want to learn what behavior is acceptable and rules and laws and how the government enforces them. You are living in a house with an animal who speaks a completely different language and understands a completely different social system. Not understanding this is how unwanted behaviours start.
The reason that there are so many behaviour problems with dogs is due to two different languages, human and canine. Learning your dog's language is essential if you want a dog who looks at you for leadership, guidance and direction. Some people feel that to learn this language costs too much and they cannot afford to do this. I understand this as getting a dog can be expensive. However, not realizing how great the cost can be of not learning about the "pack" and how dogs communcate, can be much more expensive - both in terms of money and in terms of your peace of mind and sanity.
When your dog assumes the role of the Alpha (because it does not have any choice - there must be a pack leader) it becomes very stressed which results in health problems, increased vets bills and sometimes a shorter life. Your dog can become aggressive when trying to protect you and it's pack, which can result in nasty fights with other dogs, biting children and adults, running the risk of being put down long before it's time. You become stressed out as your dog's behaviour becomes embarrassing, you don't go out for walks any more because it is too stressful and embarrassing. You stop having friends and family come round because of how your dog acts. You are not able to take your dog with you when you go out as your friends and family have asked you not to. You are frightened to leave the dog even for small periods of time dreading what the house will look like when you get back. Going away on holiday is no longer an option as no one will look after your dog including some kennels.
The reality is that your dog is never going to fully understand human language but the great news is you can learn theirs.