My dog understands everything I say.

A dog’s vocabulary rarely extends 10 words. Often we hear people say “My dog understands everything”. This is false. A dog only tries to capture a human emotion. Dogs became domestic animals at about 13.000 BC; they were the first animal species to be domesticated by man. At that time man and dog lived a similar existence: they hunted and lived in packs. Man soon recognised and exploited the dog’s abilities to hunt, guard dwellings and other animals, work with man in protecting and gathering other animals such as sheep and cattle for instance.
Recent research has shown that dogs understand humans better than any other animals even those which are genetically closer to man such as the chimpanzee. It’s the dog’s interpretation of humans signs such as a facial expression or body language that make it a superior animal. Domestication has emphasised the complicity between man and dog.
Can a dog understand certain words?
A dog will pick up a change in the tone, the loudness and the pitch of the human’s voice. If we speak to a dog in a monotone, it will never learn or progress. It will try to capture the emotion in the voice. A dog cannot understand the word as such. The word will be associated with something positive and gratifying for example: “good dog” in a soft voice with a little pat on the head.
Some breeds through their genetic make up are more prone to learning but foremost it is the dog’s environment and it’s relationship with its owner that determine it’s learning capacity.
A dog is a social animal and likes to please. So it is not so much talking but communicating. This is essential for a dog. Humans have to learn to speak it’s language, to decode it’s postures as it does with us. Humans have to be coherent: words and signs are there to reinforce and should not contradict.
Can man understand what a dog is trying to say?
That’s more difficult. Man often misinterprets what the dog is trying to say and often this leads to huge misunderstandings. I will give you an example: you have crouched down to clean the floor and the dog jumps on you – and this a natural reaction – you will completely have failed your dog’s basic training if at that stage you scold or punish it. Why? Because the dog will not understand that you are inviting it to play with you and when it engages in play, you reject it. Major behavioural problems start from innocent incidents such as this where the carer of the dogs has acted as if the dog were a human.