Children with selective mutism have a hard time speaking in some settings, like at school around the teacher. This difficulty goes beyond typical shyness — kids with SM are “frozen” with anxiety and feel unable to speak.

For a diagnosis of selective mutism, the following criteria must be met:

• The child must be able to speak in some settings but not in others
• The condition must have lasted for a month (not including the first month of school)
• The inability to speak must interfere with schooling and social activities
• The inability to speak must not be attributable to a communication disorder or a lack of knowledge of the language being spoken