Metaknowledge polar-questions as dialogic triggers for Topic-Comment constructions

The object of this paper is a discourse pattern found quite frequently in Italian conversations which consists of two Topic– Comment dialogic constructions.These are usually realized as «sai ? » and «(hai) presente ? » (both loosely translatable as “Y’know/ recall ? ”), where X is a newly introduced noun phrase, or even a subordinate clause (e.g.a descriptive when- clause), and Y can be one or more interrelated predications which are meant as a comment on X made by the same speaker who asked the initial question.Both constructions are triggered by a strongly oriented polar- question that, in these specific contexts, can employ, almost interchangeably, verbs which are not equivalent in other contexts (sapere, lit.“to know”, and avere presente, broadly meaning “to recall”), showing a semantic change of sapere due to the loss, in these contexts, of its usual restrictions in referent selection.
As often happens with other constructions of everyday speech, this dialogic pattern affords an excellent vantage point from which it is possible to better understan the interplay between live speech and grammar, a subject notoriously neglected in traditional grammar.The two constructions provide, for instance, a better understanding of the notions of sentence Topics and discourse Topics and also pose the question of whether any similar distinctions should be made within the complementary notion of Comment.Last but not least, the specific metaknowledge sequences that start the two constructions may shed some light on the role of prosody (and of intonation proper) in grammaticalization processes and on information distribution in question- answer patterns.
In short, and with a view to traditional grammar revisions, the two constructions provide yet another proof of the smooth trade- off between textually diluted (or dialogically distributed) structures and more compacted ones, providing further confirmation of the emergent nature of grammar and the interactional genesis of many (apparently) “monologic” constructions (Hopper 1987, 2011; Geylukens 1992; Couper- Kuhlen 2011; Calaresu 2018)