Stop timeline

Stop terminals the playing of a clip and returns the play head to the beginning of the clip and will only start again if an action is performed.

SL has the ability both to halt the playhead on the slide timeline:   and start it again when a click is performed:    

The problem is that they are only available when the built-in seekbar is used. FWIW, I personally almost never use it, so the attached sample shows two ways to halt the timeline until an action (click) is taken, at which point the playhead is started again from the beginning. (I was too lazy to find and insert a sound clip, so I just left the seekbar on the slide, so you can tell what it is doing.)

Like many things in SL, there is not a one-click function to do exactly every thing we want, so it is necessary to be creative with the tools we do have.