At 21 months is when toddlers begin to incorporate two word phrases into their vocabulary, such as i go, mama give, and baby play. [citation needed] before going to sleep they often. Experts group child developmental milestones into four areas:

A toddler is in the second stage, between ages 1 and 3. They've generally finished. Read about toddler development, including how to deal with everything from picky eaters to tantrum-throwers.