Stuttering when repeating sentences

Stuttering when repeating sentences I've had a stutter since I can remember. I'm 21 and has worked hard to improve since the age of 10. Recently I've noticed a new aspect of my stutter: When I repeat lines from movies, try to read a sign to someone else, I can't get the words out of my mouth. Oddly enough this does 't happen with the same severity when I read from books. I've used all of the techniques I've learned over the years, but none of it is working. Have any of you ever experienced this?