Trivia: The film's original title was "In a Dark Place," and it was written as an R-rated thriller. The film was re-written to remove some excessive sexual themes and it was re-titled "The Boy" shortly before filming began.
The Boy (2016)
Directed by: William Brent Bell
Starring: Lauren Cohan, Rupert Evans, James Russell, Jim Norton
Greta Evans: You wouldn't hurt me, would you, Brahms?
Malcolm: Okay, I see that you're... a writer from... Phoenix, Montana. You've come here to be inspired by the English countryside and to get away from the hustle and bustle of your life in the U.S. of A.
Greta Evans: No.
Malcolm: Close.
Greta Evans: Um... not at all. No.
Join the mailing list
Separate from membership, this is to get updates about mistakes in recent releases. Addresses are not passed on to any third party, and are used solely for direct communication from this site. You can unsubscribe at any time.
Check out the mistake & trivia books, on Kindle and in paperback.
Answer: First, the other answer stating his voice box was damaged by the fire is pure conjecture, and also isn't supported by the fact we hear Brahms speaking with an adult voice at one point in the climax. But to answer the original question, it's really not that hard for an adult to mimic a child's voice. Heck, voice actors do it all the time. Presuming that he's been stuck in the walls since the fire when he was a boy, he probably is used to speaking and acting like an overgrown child much of the time as he never really "grew up" mentally (as evidenced by his clumsy body language and attitude), only slipping into his "adult voice" when he becomes overtly irate or loses control.
TedStixon