The complex human speech is one of our traits that definitely separates us not only from other animals, but also perhaps from our extinct relatives. It is believed that Homo sapiens appeared about 150,000 years ago, but a sudden boost in its evolution was given by the emergence of the language some 50,000 years ago.
The speech can develop only inside a community and at the age when the brain is growing. Famous cases of children lost in the forests and found years later shows that learning the speech requires early interaction with the others.
The brain center of the speech is clearly located in the cortex, as proven by strokes affecting the speech center. One question is: which was the first, the thinking or the speech. "Functionalist" school says the thinking; "relativist" school claims that is was the language.
Many ape individuals, of bonobo, chimps, gorillas or orangutans have been taught human sign languages or to manage graphic or computer symbols. Some can learn up to 1,000 words (up to 40 new words daily), but their temporal consciousness is null.
The today's about 6,000 languages are believed to have rooted in a sole mother language, as human are believed to have formed just a small population of about 1,000 individuals 50,000 years ago. By now, three super-families of human languages.
Searching the root of the human languages, some scientific hypotheses have been formulated:
1. The etno-botanist Terence McKenna believed that the ability to process information would have increased when the first humans included in their diet psilocybin, a psychoactive alkaloid found in a sum of mushrooms. This alkaloid activates newly evolved brain parts, like the Neocortex and the Broca's area (linked to articulated speech).
Neolithic wall paintings found at Tassili-n-Ajjer (Sahara) depict a shaman with the hands full of mushrooms, fact that corroborates this theory.
2. The "evolutionist argument" sustains that the anatomy of the speech is too complex so that its emergence could be explained as the end of a chain of brain innovations, a series of mechanism whose existence supposes a clear advantage. It other words, speech served primordially for reproduction and basic humans relations linked to survival.
3. The American linguist Noam Chomsky said we are born with a speech organ, a computational system emerged through a sole mutation, a trait appeared in a moment of biological complexity. He brings as an evidence the fact that under the diversity of the human languages, the linguistic analysis reveals a common structure which could be considered innate and characteristic to the species.
In 2001, an American team found on the chromosome 7 a gene whose lack amongst the member of a family produced severe difficulties for building phrases and understanding them, even if those persons were really intelligent. This shows that language is not connected to overall intelligence and also the fact that there is a genetic base for the speech, supporting Chomsky's hypothesis.