From relative proadverb to declarative complementizer: the evolution of the Hungarian hogy ʻthatʼ

Abstract The declarative complementizer has been claimed to have grammaticalized from a relative pronoun in various Indo-European languages. The source construction is assumed to have been the correlative sentence. The initial phase of the hypothesized process, however, has remained unclear; in the explicative clause to which e.g. the Germanic that-type complementizers can be traced back (Mary knows that, that Peter is lying), that is already a complementizer base-generated in C rather than a relative pronoun in Spec,CP. This paper analyzes a similar developmental path, that of hogy ‘that’, the Hungarian general complementizer cognate with the relative proadverb hogy ‘how’, the early stages of which can be reconstructed more completely. It traces hogy back to a canonical correlative construction, and documents the subsequent stages of its evolution from a relative operator binding a variable in a correlative sentence, via a linker introducing an adjunct clause, to a complementizer subordinating a clausal argument to a matrix predicate.