Abstract
Taboo rules the world and even in science, many areas are off-limit. Some dare venture into these areas, some don't.
In historical linguistics, we just don't. When dealing with bad language, we tend to censor it, ignore it, or at least do not make it the centre of our attention.
When we do reconstruct swearwords, we often do not have the apparatus to go very deep into history, as the further you go the fuzzier the semantics become. Very few roots in PIE are being reconstructed as having a possibly vulgar secondary meaning since we cannot be bothered to deal with pragmatics.
Another problem with our general methodology is the reconstruction of morphosyntax, specifically the finer details of syntax and where it borders on lexicology "from the other side" - phrases are not considered to be stable enough to be preserved as phrases. I intend to argue here that if we use the tools of construction grammar, we can compare phrases at a certain level just like we compare any other parts of lexicon.
We can, certainly, deduce that a real human language, being a tool, must contain phrases for certain communicative functions. My case study deals with a reconstruction of one such phrase, with a function of telling someone off, rudely.