The Victorians were great hypocrites, but what little survives of their pornography is pretty foul, even by today's standards. Prior to that, even back to the age of hand-written manuscripts, books were quite expensive to produce and we have little to work with, even the Marquis de Sade is relatively free of "dirty words". I know for a fact the Greeks, Romans and Egyptians had pornography, I've seen samples, but I don't recall ever reading if they had anything comparable to obscenity.

The history of porn is pretty well understood, but I don't know if anyone has ever gone into the history of obscenity. I find it difficult to believe the Greeks and Romans had it, they didn't seem to have that giggly/naughty aspect to them, they were quite upfront about sexual matters and seemed pretty open on those issues which are usually the subject of "dirty talk". Perhaps their obscenities were of a religious nature? I don't know about them, or about oher cultures of our own time. Do pygmies, eskimos, Sherpas, and Mongolians have dirty words?