This document discusses language development from infancy through early childhood. It notes that language development begins before birth as infants can recognize voices and respond to tones by a few months old. Between 6-9 months, babies begin to recognize simple words and respond appropriately to different tones. By toddlerhood between 12-18 months, children's language abilities grow significantly as they start using words and short sentences. The document also contrasts preschool, which teaches basic concepts through play, from kindergarten which marks the beginning of formal education around ages 3-5.