Interface Fusion: A Theory of Adjacency, Operator Persistence, and Fossilized Reanalysis in Grammar

Interface Fusion offers a new theory of how grammar preserves meaning under structural compression. Using English prepositional passives as its central empirical test case, the book argues that certain fusion effects are not PF accidents, lexical exceptions, or purely diachronic residues. They are the products of a pre-Vocabulary-Insertion operation at the syntax-semantics interface. This operation, Interface Fusion, applies when adjacent operators satisfy locality, recoverability, compatibility, and realization conditions. The book develops a formal diagnostic battery, applies it to prepositional passive and related constructions, extends the analysis to fossilized reanalysis and operator stacking, and proposes cross-linguistic predictions. Its central contribution is to show that surface residue is not grammatical noise but evidence of recoverable interface computation.