Muteness or mutism (from Latin mutus, meaning 'silent') is an inability to speak often caused by a speech disorder, hearing loss, or surgery. Someone who is mute may be so due to the unwillingness to speak in certain social situations.
Those who are physically mute may have problems with the parts of the human body required for human speech (the esophagus, vocal cords, lungs, mouth, or tongue, etc.).
Trauma or injury to Broca's area, located in the left inferior frontal cortex of the brain, can cause muteness.
Selective mutism previously known as "elective mutism" is an anxiety disorder very common among young children, characterized by the inability to speak in certain situations. It should not to be confused with someone who is mute and cannot communicate due to physical disabilities. Selectively mute children are able to communicate in situations in which they feel comfortable. About 90% of children with this disorder have also been diagnosed with social anxiety. It is very common for symptoms to occur before the age of five and do not have a set time period. Not all children express the same symptoms. Some may stand motionless and freeze in specific social settings and have no communication whatsoever.
Alalia is a disorder that refers to a delay in the development of speaking abilities in children. In severe cases, some children never learn how to speak. It is caused by illness of the child or the parents, the general disorders of the muscles, the shyness of the child or that the parents are close relatives.
Anarthria is a severe form of dysarthria. The coordination of movements of the mouth and tongue or the conscious coordination of the lungs are damaged.
Aphasia can rob all aspects of the speech and language. It is a damage of the cerebral centres of the language.
Aphonia is the inability to produce any voice. In severe cases the patient loses phonation. It is caused by the injury, paralysis, and illness of the vocal box.
Conversion disorder can cause loss of speaking ability.
Feral children grow up outside of human society, and so usually struggle in learning any language.
Autism People with autism sometimes don't speak.
Most intellectually disabled children learn to speak, but in the severe cases they can't learn speech (IQ 20-25). Children with Williams syndrome have good language skills with mean IQ 50. Children with Down syndrome often have impaired language and speech.
Symptoms of selective mutism
Hearing mutism is an obsolete term used in the late nineteenth and early twentieth century for specific language impairment.
Akinetic mutism is a state in which the individual is unable to speak or move.
Some mute patients have adapted to their disability by using machines that vibrate their vocal cords, allowing them to speak. Oesophageal speech can give some speaking ability. Others learn sign language to communicate.
Computers also facilitate communication, both with smart phones and the Internet. Many augmentative and alternative communication devices exist to allow people to communicate; these include "text-to-speech" devices and/or software programs, which turns typed text and/or a button loaded with messages into electronic vocalizations, enabling the mute and the speech-impaired to "speak".
Other techniques of the augmentative and alternative communication include: