Hypothalamus is an area of the brain that produces hormones that control:

Body temperature; Hunger; Mood, controlling many bodily functions including the release of hormones from the pituitary gland.
By age 6, children know an astounding average of 13,000 words. Their sentences are longer and not as simple. But even more amazing is the new complexities in their thought processes. Their wheels are constantly churning. With this deepening, you’ll see a change in how they use language to express thoughts and ideas, uniquely their own.