At this stage, toddlers use all their skills to become good problem solvers. They begin to understand the patterns and actions they need to perform, and in what order, to reach a goal-this is known as "motor planning." Through imitation, they come to understand the functional use of objects and use that knowledge to be effective in the world. They learn that some behaviors lead to certain reactions, for example, that putting away toys will earn them a hug from mom or dad.

Becoming a competent problem solver is critical to child development in many ways, since it means that children understand how to get their needs met through action. For instance, they can find a loved one in the next room, or get a caregiver to pass them a toy they're reaching for.

Speech generally develops during this stage, but there is wide variation in when and how children develop language. While some children have hundreds of words and are quite verbal by the end of this stage, others rely more heavily on gestures and don't have as much spoken language. Don't worry too much about where your child falls in this continuum: As long as children are effective communicators via gestures and sounds, their language skills are likely to catch up.