Is there a way to hide a message in an audio file and hear it by playing it in reverse? Like if you play the audio file forward, it will skip my secret message and just play the next frame, but is there a way to play it backwards and hear the secret message?
There are a couple techniques for this that I'm aware of, one is called Backward masking. Not to be confused with the other, Backmasking.
Backmasking is arguably intentional. Regardless, it's a method of recording something backwards onto a track, as it's explained in this wikipedia article.
Backwards Masking is where there are subtle sounds or messages played in very specific and very intentional parts of a recording with the intention that the average audience member will not notice that the secret message is there, it can be done as explained in This wikipedia article.