Can a deaf person sound like Shipka's character?

Although I can't recall having met an actual deaf person all my life through, I was wondering about Shipka's character, who seems to bear little to no speech impediment, in spite of her condition.
Marlee Matlin comes to mind, and the way she talks is a whole different deal.
Her idiot classmates make fun of her, but she never sounds like it, at all. She just seems to talk a bit slower than the average non-deaf person. Ally is phonetically close to perfection, and she doesn't even seem to be challenged by that low-frequency tone slips that, at the very least, cinema tends to portray as typical of deaf people. Can that be related to the fact she wasn't born deaf?
To be fair, Tucci's voice-over at the beginning makes clear she proved herself being gifted in adapting to losing her ability to hear. Are we therefore supposed to think of Ally as someone with extraordinary skills of that sort? Or is rather common for somebody who loses hearing to recover that well from speech impediment (or even never going through it)?