Grammaticalizzazioni polifoniche o “verticali” e sintassi dialogica. Dagli enunciati-eco ai temi sospesi: l’infinito anteposto in strutture del tipo “mangiare, mangio”

Dialogical repetitions (e.g., different kinds of echoes and echo-utterances in general) have important effects on grammar and discourse which are often neglected or overlooked: on the one hand, they are often the trigger of “polifonic” or “vertical” types of grammaticalization, i.e. grammaticalization across clauses from different turns in conversations; on the other hand, they can provide one of the plainest explanations for the emergence of marked constituent orderings (e.g., left dislocations, hanging topics, etc.) in many responsive clauses. Some uses of the “free” infinitive are a good case in point. There are, in Italian as in many other languages, a number of apparently idiosyncratic but very productive constructions that require a free (non subordinated) infinitive. I will take into consideration two different types of free infinitive constructions which are usually considered unrelated: i) those generically known as “Exclamative infinitives” in Italian, “Incredulity response constructions” and “Mad Magazine sentences” in English, “Dense Constructions” in German; ii) those with a preposed infinitive which functions as a kind of hanging topic in a Topic-Comment utterance articulation. Through the analysis of their (con)textual conditions in dialogical discourses, I will argue that the infinitives display echo-functions in both types of constructions and, especially in the (ii) case, it is precisely this fact that allows the infinitive to act both as a (hanging) Topic and an ana(cata)phoric encapsulator