...disable the sound...
Turning down the master volume in the options/sounds panel is all I do - tbth, haven't seen a dedicated on/off switch but really haven't looked to hard

.../clearallqueuedabilities...
I 'think' that the above can be written shorthand as /ca - but not entirely sure - adding to this - there are two very similar commands yet I haven't found a decent explanation of what differentiates one from the other