OK ben, here's an idea:

Write a new function called: GoPlay()

In this function you call the Play(#) function and pass it two parameters, the # of the hidden item to play and how long it takes to play.
[code]
var PlayMe = 0;
var Delay = new Array(size); // size = number of items to play
var ID; // To ID the timeout.

Delay[0] = 2000; // 2 seconds
.
.
.
Delay[size+1] = 0; // Tells it we're done

function GoPlay() {
  play(PlayMe, Delay[PlayMe]);
  ++PlayMe; // To get the next one to play.
}
[/code]

Now, you play function will need to change like this:
[code]
 function play(sound, delay) { 
   document.embeds[sound].play();
   if(delay == 0) {
     clearTimeout(ID); // We're done playing things, clear the timeout.
   }
   else {
     ID = setTimeout("PlayMe();", delay);
   }
 } 
[/code]