Solo try-outs?!?!?

okay, so for band I we are doing this song about the civil war, vand our conductors want someone to recite the gettysburg address during the song. I luv acting and talking (lol) so i signed up to try out for the part, but sometimes I stutter and talk to fast. I've practiced every day and tried to slow down and talk clearly but I always end up speeding up bye the end. Any advice on what to do when I practice/get ready for tryouts?!?!?