The `fadeXXX` commands exhibit some inconsistent behavior.
For instance, the `fadeRadio` command can affect the UI sounds (e.g. button click):
0 fadeRadio 0; //can't hear button clicks, etc. anymore
And `directSay` is not affected by `fadeSpeech` (which is what it sounds like it does) and instead is affected by `fadeRadio`:
0 fadeSpeech 0;
_somUnit directSay "SentAmmoLow"; //you can still hear the unit
0 fadeRadio 0;
_somUnit directSay "SentAmmoLow"; //now it works