If ghosts can indeed communicate through voice, then they certainly have the ability to say “boo”. But why waste all that energy saying something that really isn’t going to scare anybody except for a group of 8-year old’s at a slumber party?
So where did Hollywood get the notion that all ghosts say the word “boo!” to try and scare us? According to Merriam-Webster Dictionary, the word “boo” originates from the Middle English “bo,” which was used as early as the 1500s.
However, the earliest record of the actual word “boo” being used in print dates back to 1738. According to the author at the time, the word “boo” was used as a way of frightening crying children living in the north of Scotland.