system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why are some people mute?
gpt
There are many types of mutism. Sometimes it's a problem with their brain's ability to process language, others suffer from selective mutism where they get so uncomfortable in certain situations that they can't speak, others are deaf and can't repeat what they can't hear, some have paralyzed speech musculature, etc...

Could you be more specific?