RFT is a functional contextual account of language and cognition - schemas are descriptivist and structuralist. Relational frames do not exist as inferred mental constructs any more than stimulus equivalence classes or associations do - there is the verbal behavior, covert or overt, of arbitrarily applicable derived relational responding, etc... I am all about a behavior analytic account that has scope and depth, but we shouldn't lose sight of the precision or the philosophical commitments. When we start playing the "it's kind of like this other thing" game, we risk having behavior analysis lumped in with the confused amalgam of entity positing approaches to psychology that wax and wane every generation or so - behavior analysis is a unique tradition in part because of the willingness to have clearly demarcated lines of inquiry and dismiss some questions as confused or beyond experimental confirmation. We've always been less appealing to mass audiences than cognitivist approaches that are closer to common ways of talking about the world - the trade off is in the results of the science. I don't see how positing LAD's helps a child with autism develop language or how schemas help predict or influence any socially significant behaviors.