Feral children have either grown up in the wild, alone or raised by animals, or have been confined by others and denied social interaction with humans. Feral children lack language skills, and many lack the ability to learn language when they are reintroduced to society.
Reports of feral children date back to the 14th century. The most renowned case concerning the language instruction of a feral child involves a child named Victor, who was found in France in the 19th century. Dr. Jean Itard attempted to teach Victor language skills every day for five years. Itard used a reward system to encourage Victor to speak. Although Victor never learnt to use language adequately, he did learn to express emotions and affection.
Children acquire language skills as a means to interact with others in their environment. Feral children live in isolation without other humans to communicate with. Thus, feral children do not develop language skills. Feral children may imitate animals sounds, such as barking or bird calls.
Feral children usually never acquire fully functioning language skills upon returning to human civilisation. Some may learn a few words or some sign language. Both the acquisition of verbal language and sign language require the same neurological processes.
Many scientists believe that language development must occur during the early childhood years. Once a child passes through early childhood without exposure to human language, the innate ability to learn and process language may be mostly lost because of neurological changes that occur around the time of puberty. In particular, these children have great difficulty learning the grammatical and syntactical aspects of language. The best outcome results when children receive language instruction before the onset of puberty.
Some researchers have noticed similarities between feral children and autistic children. Feral children and autistic children both struggle with social interaction and have difficulties displaying empathy. However, feral children do not show other typical autistic symptoms, such as sensory issues and repetitive movements. Also, many autistic children learn to use language to communicate effectively. In addition, some researchers wonder whether feral children were abandoned because of autism or whether symptoms similar to autism resulted from the abandonment.