Electronic Voice Phenomena is an sound that is captured on audio device that resembles speech, voices, phrases or sounds that you may not hear on your own that no physical or reasonable explanation could explain. Common beliefs are that spirits may try to communicate to the living through EVPs.
These sounds are not typically heard when recording, only in playback.
Here are a few that I have captured so far in ghost hunting experiences. *NOTE* I would never contaminate my EVPs. The sounds, voices, and words you hear on these recordings are real.
In this recording, I was cleaning up and picking up a bag. You hear me say something about the rattling being my bag, when you can hear a voice (very strange sounding, at that...) say "my bag".