How do the persons who decide to become "voice off" (can speak) fit the above re: "mute"?
"Mute" refers to someone who has a physiological condition which prevents them from being able to form speech or meaningful vocalizations - for example if someone has had a form of cancer or tumour which has required the removal of the voice box, or an injury which paralyses or damages the vocal cords.
In some cases extreme emotional trauma (or physical brain injury) will cause someone to become temporarily mute, because of the way the brain itself has reacted to that trauma.
"voice off" is a choice that someone who is able to from speech-sounds makes.
There are a number of reasons people elect to go "voice off", including:
They have a lot of difficultly producing speech which is clear enough to be understood by family, friends and espeically strangers.
They feel very self-conscious or have been made to feel embarrassed about the way they sound, especially if people have mocked, teased or made generally cruel or unkind comments about their speech.
Situations have repeatedly occurred in which the hoh/d/Deaf person has interacted with hearing people who upon hear their voice decides that the Hoh/d/Deaf person is severely mentally delayed and begins treating them as such, even when told outright that the person's speech is because they are hoh/d/Deaf, not due to any type of "mental defect"
In situations like this - people may decide to go "voice off" either in certain situations, or entirely and instead use text, gesture and sign language to communicate.
I hope that helps?