Selective Mutism (SM) is an impairing behavioral condition in which a child fails to speak in certain social situations despite speaking regularly and normally in other situations. SM presents a significant mental and public health problem due to impact on the social, emotional, and academic functioning of young children at a critical point in their development. SM is closely related to childhood social phobia, but it cannot be treated in the same way because of the young age of the children affected, their lack of speech in the treatment setting, and the need for significant school...