For a child with moderate to severe CAS, we (meaning myself as well as the child's family) will start with a small target list. We will use the sounds the child already has in his/her repertoire, and the family will also provide a few words that are functional, as well as motivational, to help create this list. The syllable length that is achievable will also be taken into consideration. Possible words include "mom/mommy," "dad/daddy," and the child's name. I always tell my parents, "slow and steady wins the race." This also helps to improve a child's confidence in being an effective communicator. As things are mastered, we will move up the totem pole (i.e., "eat" --> "eating", small phrases, etc.).
Therapy will consist of multiple practice trials of the same word. Multiple repetitions will be encouraged as they are necessary to help treat CAS given it is a motor planning disorder. Activities will be chosen by the child/whatever is most motivating for them. For example, if your child likes the ABC's, there are 26 trials right there! DTTC is my main strategy approach, incorporating tactile cues/PROMPT into it if the child is receptive to it.