I'm watching the DVD for the first season of "The Catherine Tate Show." I've watched quite a few show clips on YouTube and I found very little of it funny, but now I realize that her comedy is based on the repetition of simple themes, characters who do the same thing every time you see them. I think of this as the "Addams Family" approach to comedy...and I really like The Addams Family.
So I now present the character of Helen Marsh. Whenever a professional is unavailable, Helen reveals that she specializes in whichever field is required, but she turns out to be totally incompetent. You know it's going to happen which, somehow, makes it funnier.
In this case she's an interpreter. You could make an argument that this is in some ways racist, but I disagree for reasons that aren't very edifying or interesting.