Backing is the phonological process where a child replaces 
sounds that are produced closer to the front of the mouth like “t” and “d” with sounds produced further back in the mouth like “k” and “g”.

In speech therapy, “t” and “d” are called the alveolar sounds because the alveolar ridge(the area of your gums behind the front teeth) is where the tip of the tongue touches to stop the airflow.

Examples of backing include:

• “kop” for “top”
• “gog” for “dog”
• “gime” for “dime”

It is common for all children to make errors in speech as they are learning how to talk; however, the phonological process of backing is not typical.  If your child is producing a lot backing errors, you may want to consult a school / local Speech-Language Pathologist to see if they qualify for services.