"Selective Mutism is a complex childhood anxiety disorder characterized by a child's inability to speak and communicate effectively in select social settings, such as school. These children are able to speak and communicate in settings where they are comfortable, secure, and relaxed.
More than 90% of children with Selective Mutism also have social phobia or social anxiety. This disorder is quite debilitating and painful to the child. Children and adolescents with Selective Mutism have an actual FEAR of speaking and of social interactions where there is an expectation to speak and communicate. Many children with Selective Mutism have great difficulty responding or initiating communication in a nonverbal manner; therefore social engagement may be compromised in many children when confronted by others or in an overwhelming setting where they sense a feeling of expectation."
Dr. Elisa Shipon-Blum, Psychologist at Selective Mutism Anxiety Research and Treatment Center
Anxiety BC: What is Selective Mutism
Tips For Helping Kids With Selective Miutism Go Back To School (Child Mind Institute)
Selective Mutism Group: Childhood Anxiety Network
American Speech-Language-Hearing Association: What is Selective Mutism
Sometimes It's Not Shyness (New York Times)
Finding A Provider for Counseling (Selective Mutism Association)