If you want to use sound files for the mute and unmute self messages, you will get the same message played for both mute and unmute.
Could this be split into separate messages, so you can have one soundfile for mute and one for unmute?
Would love to have this option, too. I came from Teamspeak and there you had a female voice saying "Microphone muted" and "Microphone activated" depending on your current state. Now with Mumble, I often forget if i muted myself earlier or not and have to ask my teammates if I'm muted, because the sound is the same for both actions. That's the only thing that bothers me with Mumble ^^