The book describes the results of experiments of the last third of the 20th century, proving the ability of anthropoid monkeys and some other higher vertebrates to master the simplest analogues of human speech - to use "intermediary languages" The first part gives an outline of modern ideas about the elementary thinking of animals, the second sets out the history of the search in monkeys for the rudiments of human speech and modern research on this issue, analyzes the properties of the “language” that apes master. It is shown that they are able to assimilate the meaning of hundreds of signs (gestures and lexigrams), use them in different contexts, including completely new situations, use synonyms to refer to the same subject. They can resort to deliberate deception, communicate information known only to them, enter into dialogues with each other. It also turned out that monkeys spontaneously combine signs in accordance with the rules of grammar and understand the meaning of the order of words in the sentence when referring to them. Bonobos, who began to be taught a language-intermediary from six months of age, learned not only the language of lexigrams, but also understood the oral speech of a person at the level of two-year-old children.