Cognitive development and language are natural in that we are born with the capacity to begin learning language. Vygotsky held that language develops in stages. I believe it develops based on our environment and circumstances. The approach of neuroscience on the understanding of learning has shown how the plasticity of the brain stores and processes information how that placitity impacts learning and observable behavior. It also has shown the "lose it or use it", where learning is a skill that changes the brain but these changes revert when we stop practicing a certain skill.