The essential feature is the persistent failure to speak in specific social situations (e.g., school, with playmates) where speaking is expected, despite speaking in other situations. The disturbance must last for at least 1 month and is not limited to the first month of school (during which many children may be shy and reluctant to speak).
A pattern of continuously refusing to speak in almost all social situations, including school, even though the child understands spoken language and is able to speak.
A consistent failure to speak in specific social situations in which there is an expectation for speaking.
Selective silence in a child who speaks freely in very family circumstances but refuses to speak in specific social circumstances.
the consistent failure to speak in specific social situations where speech is expected (e.g. school) despite speaking in other situations (e.g. home).
the inability to speak in specific social situations in a child or adolescent who can and does speak in other situations.
Selective mutism is a social anxiety condition, in which a person who is normally capable of speech is unable to speak in given situations.