Human speech developed after human body and brain size, shape, features and abilities started to approach their distinct and unique forms.
Among the abilities that humanity has developed, speech has played one of the most significant roles in cultivating culture, developing communication and understanding the world people move in. Though communication is not exclusive to humans, nor is it the most advanced and nor is it the most universal, no other specie has been able to manipulate speech to the level of utilization that people seemed to have developed it.
The evolution of a gene FOXP2 gene is closely studied in researches that are focusing the genetic roots of the development of speech. Though speech is essentially a social action, there are evidences that indicate that both genetic expression and evolution and positive selection are involved in the development of speech and other methods of communication. One of theories is the development of speech is in line with the socialization and the development of the neocortex. Among animals that have very socialized lives like those of primates and marine mammals, the neocortex is significantly more developed.
The significance of FOXP2 and the identification of other genes that have consequences to language development are still in its infancy and will need more detailed language mapping of the human brain and a control specie, such as that of a chimpanzee, before a clearer understanding can be achieved. Researches so far have concluded that FOXP2 is a stored up and may even exhibit intermittent dormancy. It exhibits almost no variation among humans but a variation in two amino acids is exhibited in the genes of chimpanzees and orangutans, another close relative of humans.
As a transcription factor, FOXP2 emerges as a dominant mutant autosome in the heredity of the deficiency of motor skills that lead to dysfunctions in speech, communication or language.
