This paper looks into the interactional basis of the grammatical format of parentheticals. It will be argued that such a basis can be found in abandoned or broken off units of talk in conversation which are not immediately recycled (repaired) but whose activity status is attended to at some later point of the emerging talk. These abandoned/broken off units, then, are not erased or "overwritten" by the subsequent structure, but their projectional force remains valid and needs to be attended to by recipients. On the interactional plane, the paper focuses on those post-break-off structures which introduce subsidiary elements of talk (often materials qualifying or specifying the upcoming main point of the turn) and after which the speaker returns or attempts to return into the broken-off/abandoned structure.