Other mistake: Before the battle, the leader of the waterbenders says that he will have everyone extinguish as many sources of fire as possible. When the firebenders come up from the ground at the start of the battle, all of the torches lighting the city are lit.
Audio problem: At the beginning, when Zuko says "Look, Uncle!", his mouth doesn't move.
Continuity mistake: During the scenes at the Northern Water Tribe, there is a cut in the middle of Aang's lower lip that occasionally will disappear and reappear.
Other mistake: When Aang creates the ice spear things during the battle, he throws them into the ground surrounding a few firebenders. The firebenders freeze as if frozen entirely in ice, despite being only caged in by ice spikes.
Factual error: Zuko pulls out a family portrait out of his shirt and the portrait looks nothing like the characters in the movie, they look more like the cartoon characters.
Continuity mistake: When Aang leaves the room where Zuko and Iroh test him for being the Avatar, he is not carrying his staff, but outside it is suddenly in his hand.
Revealing mistake: During a large battle scene between the Fire Nation and the Northern Water Tribe, the camera pans to reveal a Fire Nation soldier fighting with no one.
Revealing mistake: During the first conversation between Fire Lord Ozai and General Zhao we can see that Ozai's eyes move from left to right while he looks in the direction of Zhao's chest, this revealing the use of a prompter.
Answer: The TV show Americanized the pronunciations whereas the movie said them correctly.
The show is American, so with original characters you're allowed to say them how you want.