Two elements are necessary for the development of any skill: The physical (phylogenetic) capacity for the task, and experience with the task. This experience can come from necessity – you can easily learn to climb a tree to evade a bear – or from having been taught by design or simply by observation. All living species have the capacity to learn from their environment and this is over and above the basic skills we are gifted with by nature. Most species have some innate skills (even if a simple reflex) in particular areas that allows them certain advantages when dealing with the challenges of survival and protection of the community.
The capacity to speak and evolve communication is arguably what distinguishes us from our other earthly cousins, plant and animal, and arguably what kept us from disappearing from the face of the Earth many thousands of years ago.
Language is not unique to humankind and is demonstrated frequently in the world around us, if our ears and eyes are open. Regardless of the creature, be it amphibian, avian, mammalian aquatic, or the many others that utilize and are dependent upon common codes of communication, they are gifted with the neural substrates to provide the mechanisms to perceive and to produce language. All of these creatures are born into environments where language is used and, like walking, flying, or swimming, they simply learn to use it.
Look at these two young boys, under a year old, demonstrating perfectly the precocious surfacing of formal language as a natural expression of their genetics and environmental experience: Click Here To See The YouTube Video
The neural underpinnings of this extraordinary behaviour are only now beginning to be appreciated. They may never be fully understood. Language and speech seem to follow some general rules described in the neural and behavioural sciences and there are virtually unlimited reasons why a person might have some difficulty producing or receiving language code. For the most part, most common learning and reading difficulties can be overcome with directed and thoughtful therapeutic intervention. Some disorders are based more in neurological dysfunction and these are typically more difficult to manage.