Pretty sure you can play all the sounds without knowing file name with
Code:
PlaySoundKitID(ID, ["SFX","Music","Ambience","Talking Head","Master"], [forceNoDuplicates], [runFinishCallback])
or
Code:
PlaySound("sound", ["SFX","Music","Ambience", "Dialog" or "Master"], [forceNoDuplicates])
Also it's not possible to know what sound plays at certain time.
There's a list of all soundKitID's (for PlaySoundKitID) and sound names (for PlaySound):
Click