Mysterious voice at school

I was in my school’s corridor once, everyone was in class, so I was completely alone. I heard someone ask me what I was doing there (they even called me by name). There was absolutely no one there istg. After five minutes it happened again.
One may think it was a classmate playing a joke on me, but the voice used a language not many people in my school use (it’s a regional language and most people in my school always spoke in spanish). So really, no idea what actually happened.