12 Huge Problems With Harry Potter Movies (Nobody Admits)
3. The Effect Of The Polyjuice Potion – The Chamber Of Secrets/The Goblet Of Fire/The Deathly Hallows
When adapting a novel, there are always going to be changes to the source material. Some aspects of the original story will be altered or removed, and new things will also be added. Unfortunately, the filmmakers complicated the Polyjuice Potion purely for the sake of it.
In The Chamber of Secrets, Harry and Ron both take the Polyjuice Potion, and in terms of their appearances, they look exactly like Crabbe and Goyle. But for reasons that are never explained, they retain their original voices. Whilst this does lead to a few comedic moments, there was really no need to impose this rule.
Said rule is then abandoned in The Goblet of Fire when Barty Crouch Junior transforms into Mad-Eye Moody. But in both halves of The Deathly Hallows, the filmmakers revert back to the rule established in The Chamber of Secrets. This can be seen during the Battle of the Seven Potters and during the Gringotts heist.
It would have been much easier if the filmmakers had just stuck with Rowling’s version of the potion. This would have avoided any inconsistencies and saved a job for the sound department.