I have several students who created separate keynote slides with narration using the recording function. I would like to combine their slides into one new slideshow while keeping the narration. Just dragging the slides into a new keynote isn't working.

Ms,

Your best bet is to link the presentations using the Hyperlink Inspector. Caveat: Each of your student slides needs to be open in the background - I'm not sure how many is the maximum Keynote Files that can be open simultaneously, but it is worth a try.

If each presentation currently works fine, you can hyperlink to the presentation from another presentation without trying to move audio files (which you won't be able to do).

The audio narration recorded on their slide is treated like an audio file embedded in the whole document, similar to having music play across many slides.