Early brain development is marked by a steep increase in synaptic density.

Between the ages of 18 and 24 months toddlers have learned and use two notable words. What are they?

"here" and "go" "mommy" and "daddy" "bye-bye" and "hi" "no" and "gone"

Bilingual preschoolers

A) are usually delayed in one or both languages. B) often have poor phonological processing skills. C) rarely mix the two languages in their everyday speech. D) can acquire good-to-native ability in a second language, depending on their exposure to it.