Why can't you scream in dreams?
Approved answer
Understanding Why Screaming in Dreams is Difficult
One reason you may find it hard to scream while dreaming is that the brain might be inhibiting certain functions during sleep. This includes the ability to vocalize, as the body is in a state of muscle atonia, which prevents movement. Therefore, even if you feel the urge to scream in a dream, the physical ability to do so is suppressed.