IMO the ability to speak was etched into the brains of humans and has always been their calling card.  This language, with assistance from parents, has been fostered throughout the generations.  However, there are those unlucky souls who because of parental disinvolvement were never offered the finer arts of language. 

Because of the initial plasticity of myelin sheaths, early
learning experiences are important for the individual.
However, the contents of brains cannot get inherited, and
the development of language in humans as a species
did not occur by "etching" and to suggest otherwise, by
"memes" or whatever, is Lysenkoist nonsense. Any
changes in the brains of humans as a species occurred
purely by natural selection. It is possible that the human
environment may have been affected by social changes
at a species level, and this in turn may have fed back
into the selection process by changing which qualities
were selected for, but the only *mechanism* by which
evolution occurs is natural selection.

Regards

Ed.