"Professor, do you have a moment to speak privately," a timid voice whispered.
"I shall make time. Come along, Potter," Snape answered leading the boy-who-lived to his private office before asking, "What is it?"
"Sir, I've been hearing voices-well a voice-and every time someone ends up frozen-or, well...a cat ends up dead. Ron and Hermione don't hear anything, so I'm worried I'm going crazy. But I also think whoever I'm hearing is responsible for the things that are happening, sir," Harry hurried to explain as he focused intently on the fingers fidgeting in his lap.
"Hmm, interesting indeed, Mr. Potter. Well, crazy people don't know they're crazy, so I assure you that is not your ailment. I'd know more if you'd allow me to view your memories of the events," Severus informed the child.
Wide green eyes shot up in surprise. "Magic is gnarly. How would it work, sir?"
"You would simply have to focus on each instance this has happened. Chronologically replay in as much detail as you can every event where you've heard this voice while paying EXTRA attention to the voice. I will perform a spell which will copy those memories into this," Severus explained as he summoned a strange object before continuing. "Your memories will-download, if you will-into the pensieve as a kind of smoke or mist. Once it has cleared, I will stick my head in the pensieve and be permitted to view the memories from your perspective. Any questions?"
"No, sir," Harry answered.
"And I have your permission to proceed?"
"Yes, sir."
"Very well, Mr. Potter, begin remembering the first time hearing that voice. When you close your eyes, I will start the spell. When you open your eyes, I will end the spell and we shall wait.
With the spell completed and the memories viewed, Severus had his answer.
"Mr. Potter, the reason your friends aren't registering the voice is because the voice is not speaking English, so they tuned it out as buzzing. It appears you speak Parsletongue which is the language of the snakes, a very rare gift. With this information, I believe I know what plagues our school. I am going to converse with the headmaster, and I will inform you of any developments. Please stay somewhere we can easily find you should your assistance be required," Severus explained as he started to the headmaster's office. Before he left, he turned back to the child and added, "If you hear the voice again do NOT attempt to follow it or otherwise locate the source without either myself, Professor McGonagall, or Headmaster Dumbledore. Understood?" When the chidl nodded, Severus proceeded to the headmaster's office.