I never got around to reading what Crichton (yes, Farscape) had to say about translator microbes:
Sometimes words slip through that are untranslatable. Things like proper names, unique customs, and swear words. Especially swear words!
For instance, when D'Argo heats up I'm sure he has a mouth like a drunken sailor. But my microbes never manage to translate his actual words. All I hear are growls, grunts, and a few random syllables. It has the unintended effectd of turning all my conversations PG-13, as if I've got my own built-in V-chip. Great, I've landed in Mister Rogers' Galaxy.