Child Development, Milestones and Developmental Delay

As children grow, they learn new skills.

These skills allow them to move around and interact with their world, connect emotionally with other people, communicate their needs, and learn to take care of themselves.

This is called development.

Picture of the stages of child development. From left to right you have, an image of a baby, then a baby crawling, a baby sitting up, then a child learning to walk, and finally a child with a backpack ready for school.

Of course children develop at different rates, and this is normal. For example:

  • One 2-year old might be talking in complete sentences, while another is just starting to put 2 words together.

  • Some kids start to walk at 10 months and others not until 15 months.

But sometimes these skills might be delayed by too much. If a child is not saying any words by the age of 2, then something might be wrong.

Terms to know:

  • Milestones: a way to measure normal development. They are certain skills that most children are doing at certain ages.

  • Developmental Delay: when a child is not meeting the milestones. In other words, they're not doing certain things that kids usually do at their age.

The skills we look for as children develop are in several categories.

Here are some examples of different kinds of milestones:

  • Physical —Things like holding up their head at 3 months old, or sitting up at 9 months

  • Cognitive (thinking and learning) —Skills like imitating a movement at 1 year old or knowing some body parts at age 2

  • Communication —Skills like saying "ba-ba-ba-ba"at 9 months or waving "bye-bye" at age 1

  • Social and Emotional —Skills like laughing at 6 months or showing affection for caregivers at age 1

  • Adaptive —Self-help skills like eating, dressing, or using the bathroom

Click on the link below to download this 4-page fact sheet.  (It will open in a new tab or appear in the bottom corner of your screen.)


Sources: Center for Parent Information and Resources, CDC