Language development, for ...

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.
 Norman Doidge

Quotes from the same author

We often praise 'the ability to multi-task.' While you can learn when you divide your attention, divided attention doesn't lead to aiding change in your brain maps [lasting changes].
 Norman Doidge
Analysis helps patients put their unconscious procedural memories and actions into words and into context, so they can better understand them.
 Norman Doidge
Analysis helps patients put their unconscious procedural memories and actions into words and into context, so they can better understand them. In the process they plastically retranscribe these procedural memories, so that they become conscious explicit memories, sometimes for the first time, and patients no longer need to "relive" or "reenact" them, especially if they were traumatic.
 Norman Doidge
Thought changes structure... I saw people rewire their brains with their thoughts, to cure previously incurable obsessions and trauma.
 Norman Doidge