Is it Nature or Nurture, congenital or acquired? The answer is actually quite simple: everything is Nature and Nurture. The structure of the brain determines what we can learn and what we learn determines the structure of the brain.
A newborn baby cannot speak, it sees almost nothing, and controlled movements of its arms and legs are minimal. After being born he learns through significant changes in the brain. These are a condition for and also a result of this learning process.