highly wild idea:
If specific vibration causes specific disk latency, given a high precision intstrument, what are the chances of being able to eavesdrop sysadmins on a co-loc site? ;)
Also, to directly answer your question: The latency demonstrated is in response to high amplitude noise. For talking you'd need it to be sensitive to the frequency as well.
Perhaps you could tell if things weren't going well (lots of yelling)?