In linguistics, inverse copular constructions, named after Moro, are a type of inversion in English where canonical SCP word order is reversed in a sense, so that one appears to have the order PCS instead. The verb in these constructions is always the copula be. Inverse copular constructions are intriguing because they render the distinction between subject and predicative expression difficult to maintain. The confusion has led to focused study of these constructions, and their impact on the theory of grammar may be great since they appear to challenge the initial binary division of the sentence into a subject noun phrase and a predicateverb phrase , this division being at the core of all phrase structure grammars.
Examples
Inverse copular constructions involve nouns and noun phrases, but they do not allow the post-copula nominal to be a personal pronoun: The defining trait of the inverse copular constructions is that two counts of inversion appear to have occurred: the normal subject has inverted to a post-verb position, and the predicative nominal has inverted to the pre-verb position. The verb is a finite form of the copula 'be'. This type of inversion is generally NOT possible with other verbs.
Subject-verb agreement
Inverse copular constructions where the inverted predicative expression is a noun phrase are noteworthy in part because subject-verb agreement can be established with the pre-verb predicative NP as opposed to with the post-verb subject NP, e.g. In the inverse copular constructions, the copula agrees with the singular predicative expression to its left as opposed to with the plural subject to its right. This phenomenon seems to be limited to English ; it does not occur in related languages such as German, e.g. Nor does it occur in some Romance languages, e.g. Italian: The fact that English demands subject-verb agreement to occur with the pre-verb NP generates confusion about what should qualify as the subject NP. From a morphological point of view, the pre-verb NP in inverse copular constructions should count as the subject, but from the perspective of information structure, the post-verb NP should be the subject.
Importance for the theory of grammar
Inverse copular constructions challenge one of the major dogmas of the theory of clause or sentence structure, i.e. that the two basic constituents of a sentence - the noun phrase and the verb phrase - are associated with the logical/grammatical functions of subject and predicate. In fact, copular sentences that maintain the canonical groupings are not adequate on empirical grounds, since a very unorthodox left-branching structure is necessary, or if one rejects the canonical groupings and positions the subject inside a VP-like constituent, then one has to assume that the subject NP and copula verb can form a type of VP to the exclusion of the predicative expression.
