Kristen Stewart’s stutter in Twilight, while in line with her character in the film, has been mercilessly mocked by Twilight haters over the past couple of years. 
Kristen Stewart and Robert Pattinson during first Twilight promotional tour
However, those who have seen her other films and also seen the final Breaking Dawn film [when Stewart’s Bella Swan gets turned into a vampire] know that Stewart is capable of playing polished and poised just as much as any other actress.
Now, Stewart herself reveals the reason for the stutter, explaining [via CNN] in a behind the scenes DVD clip [from the Breaking Dawn: Part 2 DVD] that, “I've yet to play somebody who was a huge departure for me. I mean, to be completely still and controlled, and to know that your mind works faster. Being a clumsy person, it's not the easiest thing to do. The way I usually learn my lines is I learn the idea, which is why I stutter a lot in 'Twilight.'"
Kristen Stewart in a Twilight promotional image
Of course, the stutter is no longer present in ‘Breaking Dawn: Part 2’, replaced by the smooth dialect that is associated with vampires in the Twilight franchise. To see more behind-the-scenes clips with Kristen Stewart and Robert Pattinson, you can pick up the DVD and Blu-Ray of Breaking Dawn: Part 2, available in stores and On Demand now.
Kristen Stewart interview for Breaking Dawn: Part 2
