[SDPhantom]

You could do something like this.

local SongList={
	"songA";
	"songB";
	"songC";
};

print(SongList[math.random(#SongList)]);

This should print a random string grabbed from SongList. The length operator (#) returns the length of the table (number of consecutive numerical indices starting at 1). Giving only one argument to math.random() is the same as calling math.random(1,n) where n is the number you're passing it.

PS: If you're referencing sounds located in your addon folder, you need to make sure the path is formatted relative to WoW's root directory.
It should look something like this:

"Interface\\AddOns\\YourAddOn\\PathToSound"