Evolution is a slow process of adaptation of living beings to the conditions of the external environment. In all living things, this slow process is ongoing. Only the human brain has acquired the ability to evolve rapidly. With the development of the rapid evolution of the human brain, a man became a conscious, rational and human being. These qualities develop awareness of the environment and oneself, the power of speech, which also develops language skills. All other animals, like the dog, did not go through this evolutionary process and could not build speech and language abilities, so they remained at the level of instinct and reflex. Given this evolutionary path, the dog has no reason and no ability to understand speech. The dog communicates exclusively through vocal abilities and body movements. The example of voice capabilities versus speech capabilities is very different. In dogs it is AV, in cows it is MU, in sheep BE, in goats ME. All other voice possibilities are reduced to two letters, unlike a human whose language has an average of about 30 voice possibilities, ie. letters.  By combining letters, we get words that give a certain concept in communication. By combining words, ie. concepts, we develop linguistic possibilities, and through them speech, reason and consciousness. Animals, in the absence of letters, do not have the ability to compose words, so in communication they use only their vocal abilities, which they enrich with repetition, duration, tonality, pitch and the length of the pause between notifications. Deficiency in voice communication, animals, and even dogs, 90% of communication is achieved through body movements. The dog did not develop the ability to understand human speech and language abilities. He reacts to a person’s word-command only to an accented vowel and binds it to human behavior, thus reacting to a command.