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.). Being mute is often associated with those who have hearing impairments or are deaf, but other variations of muteness can be linked to those who can hear and have the ability to speak. Other causes include intellectual disability and autism. A person can be born mute, or become mute later in life due to injury or disease. The prevalence of mutism from all causes is on the order of 8 persons per 10000. 
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. Others may just whisper. The anxiety can be caused by the child being put in situations where something is expected of them or when multiple people are in the area and they are subjected to many questions.
Symptoms of selective mutism
- The inability to maintain eye contact
- Sensitive in loud crowded situations
- Social isolation and withdrawal
- Stubbornness or aggressiveness when getting home from a stressful event
Akinetic mutism is a state in which the individual is unable to speak or move  It is often caused by trauma to the frontal lobe of the head. Often misdiagnosed as a symptom of depression, it can be caused by strokes or other traumatic events which cause the victim to be unable to communicate.
Some mute patients have adapted to their disability by using machines that vibrate their vocal cords, allowing them to speak. 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 into electronic vocalizations, enabling the mute and the speech-impaired to "speak".
- Augmentative and alternative communication
- Developmental disability
- Speech delay
- Vocal cord paresis
- Page 6 in: Leonard, Laurence B. (1998). Children with specific language impairment. Cambridge, Mass: The MIT Press. ISBN 0-262-62136-3.