The main observation of the genetic theory of language is that, children everywhere in the world learn to speak very rapidly. Everywhere in the world children follow very similar steps while learning language and make very similar mistakes. All these can easily be explained by an innate ability to learn language but is very difficult to explain otherwise. This line of reasoning leads to the theory that innate propensity to language must be due to human evolution. Chomsky (1998) was the first to put forward this idea which has subsequently been modified and extended by Hauser, Chomsky and Fitch (2002) and Slobin (2004) among others.
The proponents of this theory claim that human brain, during evolution, has developed specific neural circuits, which provide human children the capability to process the language information. Neuroscience has, in fact, identified specific areas in the brain that have distinct language functionality. That is the reason some stroke victims become speech impaired if these areas of the brain are affected. Second evidence in support of genetic theory is development of vocal tract which makes it possible for humans to articulate precise vocal sounds. Genetic theory explains well how creole developed as a full fledged language in Surinam. What started as an incomplete and restricted language form by escaped slaves living together and speaking many different languages, transformed into a full language by their descendants. However, this theory fails to explain why a hearing child of deaf parents, even when exposed to television, could not speak well (Bard, Sachs and Johnson, 1981)
The other theory about origin of language focuses more on social interaction and suggests language to be an evidence of a child’s cognitive development process. Children begin by imitating adults, specially their care-givers. Language acquisition also is a part of social interaction. But unless and until a child