Every child is a unique individual who develops at his or her own rate. This is easy for me to say as a speech-language professional, but not so easy for me to remember all the time as a parent. When we're in the midst of raising our little ones, it's easy to get stuck on what they "should be doing" or what their older siblings did at the same age. I, too, am guilty of this. I have 2 children less than two years apart in age, and I admit it -- I compare them. But in the area of early childhood development, it is so important to keep the perspective that indeed every child is a unique individual who develops at his or her own rate.
While it is important to remember that to an extent we need to let our kids take things at their own pace, some differences in development can serve as indicators of a developmental delay or disorder. Over the course of many years, speech and language researchers have come up with norms to describe the typical pattern and rough time-lines for feeding and communication development in kids in order to help guide parents and teachers.
A "norm" by definition is just an average ... an average age at which most kids do things -- a guideline by which to make judgments and help us know when intervention might be needed.
The norms below are posted in hopes of providing some guidance and guidelines for tracking development and to help bring awareness to when children might need more help.