Over the last eight centuries there are reported cases about children who grew up without language, some of them never looked after by any human or scientist, left in the woods or other places by their parents, or abused by the same. They were named with the notion feral or wild children.
The first case of such a child was noticed in 1724 near the German town Hamelin. 13th year old boy Peter, who was described as naked and wild child, was enticed into town and become a subject of great interest because of his strange behavior and most important because of his lack of language. Later on the King George I of England adopted him, where he lived the rest of his life. During his life Peter never learnt to talk, he never smiled, and kept that abnormal behavior of a wild animal. Nowadays scientist and linguist do not consider Peter as feral child. Counting the fact that he was living in the woods for one year and then returned back home, where he was living for year or two, continuously abused by his father during his stay at home and at the end was abandoned in the woods, scientist believed that his lack of language and strange behavior came as consequence of the torture by his father.
The second case is the boy called Victor, who was apparently lived his childhood naked and alone in the woods of Aveyron, Southern France at the end of the 18th century. When he was found at the age of 11, Victor succeeded to escape from the village, but after year and a half he comes back among the humans. It was clear that Victor can hear, but with no any additional reason he was taken to the National Institute of the Deaf in Paris, where ended up in the care of the young medical student named Jean Marc Gaspard Itard. Itard adopted Victor and looked after Victor for many years. His aim was to teach Victor to speak and to express his human emotions. Victor succeeded in understanding language and reading some single words, but unfortunately that was the highest language level that he succeeded to reach. During his life he never learnt to speak the language as each human being, only learning to spell the word ‘milk’ and the phrase ‘Oh my God’, but mastered in expressing his human emotions towards other people. Victor’s attempt to start acquiring the language for the first time at the age of 12 is just another evidence for the brain lateralization before the period of puberty and impossibility to learn a language after this period, which is only justifying the existence of the critical period for language acquisition.
The third and the newest case related with the critical period hypothesis is the girl called Genie, dating from 1970 when Genie was noticed by the social workers in Los Angeles, California for the first time. When she was born her father who was abusing her mother, thought that Genie is retarded, and take care of her till she was 20 months old. Since she was 20 months old till the day was found by the social workers, Genie was locked in a dark room, tied to a potty chair and left to sit alone day after day. Some nights she was tied into a sleeping bag, which controlled her arms, and some days she was totally forgotten by her family, so she was spending the nights tied to the potty chair and sleeping in that pose. When her mother was giving food to Genie it was not allowed to speak to her, and that was the reason why Genie when was discovered by the social workers at the age of 13 did not speak any language, except the words ‘stop it’ and ‘no more’. She had some strange bunny-like walk, holding her hands in front of her. This girl did not know how to chew the food and had difficulties in swallowing the same. Genie was rescued and settled in the Children’s Hospital in Los Angeles, where a whole team starts taking care of her. After several months Genie learnt about a hundred words and her talking was limited to high-pitched noises that were hard to understand. But overall she was very silent.
During all this years of her recovery she was learning new words, but she was not able to put the same together into meaningful sentences. Her speech and sentences were telegraphic, which means she was not including grammatical tenses, modals, and plurals in her speech. The last tests that were made on her brain were shocking, because the tasks in her brain were extremely unbalanced. The left hemisphere of her brain which is responsible for the language tasks was not working. Her tests looked similar to the tests of children whose left hemispheres of the brain were removed, which explains her disability of learning a language after the age of 13. All tests done proved that this child was not mentally ill, which means that she has great difficulties in learning the language at the age of 13 because her left hemisphere that has never been used for language lost its capacity. Each human being is born with the ability to learn a language. Sooner the language is started to be learnt, better results will be achieved. Although some scientist explain Genie’s disability to master the language as a possibility that she was right hemisphere thinker, Genie’s case is the most valid and strong version of the existence of the Critical Period Hypothesis.