Grammatical interference

Two instances of grammaticalization are examined that illustrate the gradual character of change and the categorial ambivalence of grammaticalizing items. The first change is the development of the subject marker for in the English for...to-infinitive, whose expansion into new grammatical environments is shown to be steered by the historically related but syntactically distinct preposition for. The second change is the semantic and collocational development of the phrasal verb particles out and forth, which are argued to have influenced each other’s trajectory of change. Both case studies show how grammaticalization processes can be guided by connections between grammaticalizing elements and other elements in the grammar. It is proposed that such connections form the substance of gradience and can be successfully described and explained in a constructionist and connectionist model of language. This interpretation of gradience in turn can shed light on some of the sub-processes (persistence, decategorialization, paradigmaticization) and motivations of grammaticalization.