The conceptual system for teaching children a language, whether children with autism or not,
is not found in theories. Our mothers, fathers, sisters, brothers, aunts and uncles etc. showed us, guided us, indoctrinated us in a cultural practice. They taught us how to do all kinds of things with words... to make promises, to ask, to describe, to provide directions, to tell, to invite, assert, proclaim, negotiate, confirm, disagree, offer, refuse, etc.....not to tact, mand or intra-verbal. They helped us learn the rules for the use of words and the words used to express the many concepts that are a part of our language such as "what", "where", "when", "how", "why", "car", "ball", "carry, "climb", etc..
This is what we, as children, learned in our indoctrination in the practice. Guides in this practice don't need to have mastered a theory of language in order to guide well...it requires only their own mastery of the practice. Our job, as interventionists, is similar. Except in our case, rather than wait for situations or conditions to occur naturally so that we might guide children in what they might do/say under those circumstances, we need to contrive situations so to allow for pointed practice and guidance around those circumstances in which appropriate linguistic forms and accompanying words can be used... whose uses are determined by convention, not theory. Within these circumstances, there are no 'fixed responses' (i.e., responses "controlled" by the antecedent stimulus) but rather, appropriate ones. Therefore, the situation in which someone greets me by saying "Hi", does not require/demand "Hello" in return. Any number of appropriate responses can be imagined such as "Where've you been?", "How was your trip?", "I like your hair" etc. What constitutes a 'correct' response is determined by the practices of the verbal community.
It takes a great deal of time, training and careful engineering for a child to begin to master a linguistic practice. There are constituents which need to be acquired first and elements need to be drilled even before training in the practice can begin. Just like when learning to play chess...first one learns the names of the pieces, then basic moves and eventually, to consider any number of possible moves. So too in learning a language. To work outside of this framework is to only scratch at language.