im not quite sure if this is what your looking for but the use of colloquial langauge in the motel room between shiela and birdie may be a language technique and shows the audience the history that exists between these two very different characters. theres use of humour as well by both these characters which acts as a mask to hide their true fears. if you read bewteen the interview and when their alone in the room i think you'll notice that theres a difference in the way their speak. their more formal in the interview and have less of an inhibition in the motel room. this shows that they attempt to hide their real selves and put on a differnt persona when they are interviewed, again hiding their scars. stream of consciousness may also be a lanuage technique used as they go back into their memories of the past within the interview as well as out. theres probably more but thats all from me. hope it helps, sorry if it doesnt