This work explores two kinds of asymmetries within the class of nominal copular (NC) constructions under the unified theory of copular sentences deriving the two basic configurations from a unique underlying structure via raising, namely canonical vs. inverse. Using acceptability judgments, we first tested wh- sub-extraction from both determiner phrases (DPs) in both configurations. We then collected acceptability for the same sentences without involving sub-extraction, and compared these results with the acceptability of pre- and post-verbal subject placement in transitive, unergative and unaccusative predicates. We observed the following. (i) Sub- extractions from predicates in canonical form are the most acceptable. (ii) In the remaining conditions, sub-extractions from predicates are more acceptable than those from subjects, and those from canonical are more acceptable than those from inverse NC sentences. The preference for canonical NC sentences is also confirmed when sub-extraction is absent. (iii) There is a general preference for preverbal subjects with all verbal predicates (especially strong in transitive and unergative predicates, milder with unaccusatives). The best acceptability results obtained with sub-extraction from predicates in canonical form are in line with the unified theory; the necessity to occupy a pre-verbal position for (presuppositional) subjects captures all the major remaining contrasts.
