Early Literacy Tip – Right now your two-year-old’s brain is growing incredibly rapidly. “At birth, only 25% of the baby’s brain is formed. By the age of three, the brain grows to about 80% of adult size and by the age of five to 90%.” Your child’s brain is developing miles and miles of neural pathways. The things you do with your toddler actually make your child’s brain grow. 
Positive experiences in the first few years have a lasting impact on the brain.
(Cobb, What’ll I Do With the Baby-o?)