As the name implies, this function plays the specified system sound. The available sounds are extracted from /System/Library/Sounds.
Beep represents the alert sound configured in System Preferences - Sound.
Runtime is a special setting which implies the sound should be extracted from the full path of an audio file in named variable Play Sound Path. If for any reason the file cannot be loaded or played, a beep will be emitted.
The Play button can be used to preview the sound. Note that Runtime will play a beep. The duration of the play time is restricted to 5 seconds.
This statement always terminates any currently playing sound started by a previous call.