The Brain That Changes Itself: Stories of Personal Triumph from the Frontiers of Brain Science

by Norman Doidge

Language development, for instance, has a critical period that begins in infancy and ends between eight years and puberty. After this critical period closes, a person’s ability to learn a second language without an accent is limited. In fact, second languages learned after the critical period are not processed in the same part of the brain as is the native tongue.

If you ever ask yourself, “How often must I practice French, or guitar, or math to keep on top of it?” you are asking a question about competitive plasticity. You are asking how frequently you must practice one activity to make sure its brain map space is not lost to another.