Throughout history, there have been many cases of humans who have lived isolated, children who have lived without any human contact from a very young age and have been unaware of human social behavior and mainly of human language. Few cases have captured scientific and expert’s attention and have become especially important to find out answers about the way how they (Feral children, wild child, undomesticated) acquired some abilities such as gestures, adapting to temperatures better than us, relations with animals or the lack of language. Let us see for instance the following cases of feral children who were raised in completely isolation such as the case of Genie Wiley, who grew up isolated and lost any possibility to speak and Oxana Malaya who for six years spent her life living in a kennel with dogs Genie Wiley, a 13 years old girl found completely isolated was one of those feral children and quickly gained attention in 1970. Genie was kept in such confine by her parents that she never even acquired the ability to speak. Genie´s case was so important to science that experts such as Susan Curtiss, a professor of linguistics from Los Angeles, studied the case. She analyzed how Genie´s brain developed, and then applied the theory called “Critical Periods” which is when someone develops a particular characteristic in certain time, and one of those periods is language. Even though Genie was making progress learning words she was still struggling with her past, and linguistically she stopped making evolution, Susan remarked Genie lost her mental faculty to learn grammar and sentences which is mainly what involves language. Medically Genie didn’t develop the cortex, the last part of the brain that makes speech possible. She didn’t hear any word and didn’t get stimulated and that part of the brain automatically changed and got less functional. Another particular case was in 1991, when Oxana Malaya was discovered in Ukraine. Sh