Deriving the functional hierarchy

This residual core functional hierarchy (CFH) is unexplained so far by work which follows MUG. Rather than simply stipulating the CFH as part of UG, we reconcile CFH with MUG by detailing what nonlinguistic cognition must look like in order for MUG to derive the CFH. We furthermore show how an individual language develops a language-specific RFH which is consistent with the universal CFH, illustrating with a detailed account of the English auxiliary system.