Chomsky's Theory of Language Development discusses "critical periods" for learning language. Following from this theory, disruptions during critical periods should negatively affect the development of language.

Unfortunately, there are some examples from real life to demonstrate this hypothesis. Please link to and read the following regarding both a very recent and an historic case:

http://abcnews.go.com/Health/story?id=4758945&page=1

Here are some additional, optional resources on Genie:

http://documentarystorm.com/secret-of-the-wild-child/

http://www.pbs.org/wgbh/nova/transcripts/2112gchild.html

Obviously, these are both horrific cases of child abuse.

1) What does "Genie's" final outcome tell us about language (and emotional) development?

2) What cues can educators take from these tragic cases?