Children between the ages of 2 months and 5 years pass through many developmental milestones, such as learning to sit up, walk, talk and get dressed without help. While individual children may reach milestones somewhat early or late, serious delays may indicate trouble and must be evaluated by a pediatrician.
Beginning around 2 months of age, children can usually respond to the sound of adult voices with a smile and follow people with their eyes. In the next two months, babies learn to lift their heads when lying on the floor, firmly grasp objects within reach and smile at family members. Babies at this age also begin to babble and imitate sounds. Between 6 and 12 months, children develop the ability to roll from side to side and to respond to their own names. They also sit upright without support and begin speaking single words, such as "mama."
At 18 months, most children walk independently and are able to drink from a cup. An 18-month-old child can point to named body parts. Over the next 18 months, lasting until age 3, children learn to run and jump, form two-word sentences, and sort objects by shape and color. Older children are able to count, ride tricycles, and remember family names and addresses by age 5.