By the age of three, the toddler's brain has formed about 1,000 trillion pathways or synapses - about twice as many as his mom or dad have. The toddler's brain is super dense and primed for learning. When a pathway is used repeatedly, it becomes permanent; a pathway used infrequently is lost. Children whose parents speak, read and play with them during these early years have more highly developed brains with better language and learning skills.
Around age three, research indicates a growth spurt in a toddler's head circumference and a dramatic increase in activity in the two major language regions of the brain. At the same time, a toddler's vocabulary surges from about 900 words to around 3,000 words before age five.
Now that vocabulary is well established, a second language explosion occurs and involves the rapid accumulation of grammatical skills. Toddlers begin to use the smaller function words (of, to, on, the, am, in), verb endings (ing), plurals (s), and possessives. This learning is not a trial and error process; instead the toddler's brain figures out and applies grammatical rules for how different parts of speech (nouns, verbs, adjectives, adverbs) are used.
Research shows that children in all cultures learn language in the same way and on a very similar timetable from birth to age four. Parents who talk and read to their toddlers during this pivotal time help them learn the rules of grammar and acquire a larger and richer vocabulary. Language experts say that the capacity to master syntax and the rules of grammar develops at around age three. This aptitude steadily declines from about Kindergarten into puberty. Parents can take advantage of this window of opportunity to help their toddlers learn the foundations of spoken language.