Mad Dog Maguire: When this is over, me and my boys get free drinks!
Jonathan Carnahan: You can have the whole damn bar! I'm getting the hell out of China!
Jonathan Carnahan: Hey! You three-headed shape-shifting son-of-a-bitch!
Rick O'Connell: I. Really. Hate. Mummies.
Evelyn O'Connell: I think the feeling is mutual.
Jonathan Carnahan: I hate mummies. They never play fair.
Answer: Reading and speaking many Eastern languages can be entirely different tasks so it's perfectly plausible that she knew how to translate the writing but not how to speak it.