Genie was a child found a few decades ago to have been
neglected throughout her entire childhood. She was kept in a
particular room of her house, regularily fed and was given a
potty chair. Upon discovery of this and release of Genie to
the public, Genie's lack of forming a language was questioned
and people sought to find the answer.
One of the looming questions for some time was that if there was a particular period of one's life in which an initial language must be formed in order to have language at all. A scientist in particular took Genie in to record and observe her progress over time as she was taught and exposed to language. Many tapes were created, and she attracted the interest of scientists in the field from all over. As it was though, her language level never increased much over that of a 4-year old, with a fairly small vocabulary.
A previously recorded source of such an example having a child
unexposed to society, unable to pick up language, was that of
last century, with a boy named "Victor." He was found from the
woods, basically naked, unable to communicate with others at
a decent age. He was taken into custody to be trained with
others in Paris at the deaf school there. Many logs and journals
were recorded of his process throughout, noting some rather
fabulous accomplishments such as Victor being able to run
in the snow without any sign of being cold. After a number of
years, however, the future for Victor looked grim, and the
scientist taking care of Victor in hopes of receiving glory
abandoned him.