mutism
/ˈmjuːtɪzəm/noun
mass noun
1- inability to speak, typically as a result of congenital deafness or brain damage（通常指先天性失聪或脑损伤引起的）哑。
1.1
- （全称elective mutism）unwillingness or refusal to speak, arising from psychological causes such as depression or trauma（精神沮丧、心灵创伤等心理原因引起的）缄默症。
词源
early 19th cent.: from French mutisme, from Latin mutus 'mute'.