[Fizban]

Zmud and Cmud can indeed produce sound through the use of triggers, the following trigger would make a beeping sound when a skill increased if the mud sent the text "Your knowledge of <skill|spell> has increased by <#> points.":

#TRIG {Your knowledge of * has increased by * points.} {#beep}

Also Cmud supports Lua, Visual Basic, JavaScript and other real-world languages so its uses are really nearly unlimited.