I want to know whether there is a technical term, preferably an accepted one, for the following type of parenthesis (bold):
(1) You are, I believe, not healthy.
The (bold) parenthesis always consists of a subject (often a pronoun) and an illocative verb: think, believe, etc. See for Russian: Iordanskaya & Mel'čuk (2011). Personally, I'm not convinced that Iordanskaya & Mel'čuk have it right, though.
The English data are less compelling than the German data. This type of construction looks as if it could be recovered in derivational syntax theories. However, data from German throw doubt on this assumption:
(2) Sie würde dem, (so) glaube ich, niemals zustimmen.
'She would, I believe, never agree with that.'
The parenthesis in (2) shows VS-order, with the optional adverb so. Note that the parenthesis cannot be the main clause because the propositional object (the clause without the parenthesis) cannot be preceded by a subordinator, such as dass.
If you know what this construction is called, or if you should know of an analysis of this kind of structure, please post an answer. Please avoid lengthy discussions in the comment section.
Sis a clause, and "Lifting" means that the locution of the illocative verb becomes the main clause, i.e, it's "Lifted" up to the top node, while the ostensible top-node performative becomes a parenthetic chômeur. Slifting has interesting interactions with negative expressions.