Speech and Language Developmental Milestones (National Institute on Deafness and Other Communication Disorders, NIDCD) (Available in Spanish)

Description:

The first 3 years of life, when the brain is developing and maturing, is the most intensive period for acquiring speech and language skills. These skills develop best in a world that is rich with sounds, sights, and consistent exposure to the speech and language of others.

There appear to be critical periods for speech and language development in infants and young children when the brain is best able to absorb language. If these critical periods are allowed to pass without exposure to language, it will be more difficult to learn. 

This information is available in Spanish.