A Comedy Translator, or C**T, is someone who feels it absolutely necessary to ensure that everyone enjoyed and (more importantly) understood a joke or television programme, or play, or comedian, or toilet visit as much as they did, personally.
The Comedy Translator will routinely bring up elements of a joke or performance that most people would consider throwaway, or have understood anyway, in order to debate them, and in turn, prove how intelligent they are by having spoken to you about it.
The irony of the Comedy Translator is that despite their comedy name, they are widely hated.
Comedy Translator: "God, that was absolutely HILARIOUS, don't you think?!"
You: "Yeah, I suppose it was quite good"
C**T "No, no, no, no. It was HILARIOUS, did you get that bit when he brought the cat in, and he was stuffing it into her face?! That was an in-joke about famine, I know this because it was on his '1984 At The Palladium' re-released DVD commentary..."
You: "Absolute silence on the way home, please"
When a person attempts to ride the coattails of a joke that someone else has just made. The leech joke will, in one-hundred percent of cases, involve the same basic premise as the original joke, though the leech may slightly alter words to attempt to inject some degree of originality into proceedings.
The leech-joke will commonly receive:
a) a few charity cough-laughs
b) a look of confused disdain from everyone within earshot.
c) a violent reprisal
A Social Example of a Leech-Joke in Practice:
(To group at table)
Ted: ... so essentially what she's saying is that she did not notice a vas deferens
(at same table, seconds later)
Derek: (loudly) Yes, because they both had penises, but neither was very different, at all!
(Cue coughing and shoe-gazing around the table as fellow diners try desperately to avoid eye-contact with Derek.)