"I know it wasn't rape-rape. It was something else but I don't believe it was rape-rape."
Whoopi Goldberg, on the rape trial of Roman Polanski
Contrastive focus reduplication (usually abbreviated CR) is the name for a linguistic phenomenon in English that repeats (reduplicates) a word or phrase in order to contrast it with a similar idea that might be expressed by exactly the same word or phrase. The reduplication provides what linguists call "focus," which is to say that it zooms the listener's attention in on a particular element of the sentence. In the case of CR, the focus is on the most literal or typical of the meanings that can be gleaned from the repeated phrase.
Doris: Feel like a little lunch, Millie?
George: Ah, actually I have plans today.
Doris: Really?
George: Yeah, it's kind of a lunch date.
Doris: Oh.
George: I mean, not a DATE-date.
Dead Like Me
The reduplication that George uses in this conversation hinges on the ambiguity of the word date: in colloquial English, it could mean any meeting at an agreed-upon time, or, in its more focused sense, it could have a romantic connotation. George rushes to clarify that there is nothing romantic about this date by saying that it's a date (in the first, broader sense) but not a date-date.
Sometimes the connotative field of a word expands over time, to the point where the original word is ambiguous when it was not ambiguous before. CR is one way to deal with this problem, but not the only way. (Think of how what used to be described simply as "mail" now needs to be called "snail-mail" to distinguish it from e-mail.) For example, if you tell a friend that you need to go to the bank, she might ask if you mean a bank-bank, which is to say a building with lines and ropes and tellers, as opposed to just stopping off at an ATM.
The quotation that I used as the epigram for this post is a bit more complex and definitely more politically charged than the other examples. In this now-notorious interview, Whoopi Goldberg was trying to create a distinction between "real" rape ("rape-rape") and what Roman Polanski did to a thirteen-year-old girl (which was apparently just "rape"). The ubiquity of CR in English makes it so that no native English speaker would misunderstand what Goldberg was trying to do: by reduplicating the word "rape" in her sentence, she was focusing on the contrast between the kind of rape that ought to be punished and the "milder" crime that she imagined Polanski committed. The distinction is, of course, ridiculous, and Goldberg has rightly been called on it numerous times. You're either a convicted rapist or you're not, and Polanski is a convicted rapist. It is simply impossible to create a meaningful analogy along the lines of ATM : bank-bank :: rape : rape-rape.
But the Goldberg example is interesting linguistically, because it uses a relatively new phenomenon in English in an attempt to make a quasi-legal distinction in a public forum. It's frequently asserted that there is no linguistic reduplication in English along the lines of what you find in, e.g., Chinese (where ren means "person" and renren means "everybody"). But reduplication can be found in English, and it does provide clarification to some terms that can't easily be expressed in other ways.
Further Reading