You can play back the audio associated with a slide to test it.
To play the audio associated with a slide
In the Presentation Layout pane, select the desired slide.
Click Slide > Play on the menu,or click on the toolbar.
If the slide is a static slide, the audio associated with the slide will play.
If the slide is a movie slide, the movie and its associated audio will play.
To stop playing, click Slide> Stop on the menu, or click on the toolbar. If a PowerPoint slide is being played back in Slide Show mode, this will exit the Slide Show mode and return the slide to Edit mode.