Suspending listening does not mute your microphone, it instructs VoiceAttack to ignore commands that don't start with a "Make VoiceAttack Start Listening" action or aren't combined with the "Override listening if my spoken command begins with" phrase, specifically so you can use a spoken command to resume listening.
The listening state is only changed when something instructs it to change, however; VoiceAttack does not resume listening without user input in its default configuration.