Machine Machines and Number Numbers

I wonder what you’d call a machine whose function was to make automatic teller machines (ATMs). Would it be called an ATM machine? Well, no, of course not, since ATM machine means the same thing as plain old ATM: If you see a sign saying “ATM machine inside” when you enter a grocery store, you will find an ordinary ATM, and you won't find some other kind of machine that has something to do with ATMs.

This kind of redundancy also occurs with acronyms whose final N stands for number. The ones I can think of right now are PIN number, VIN number, and ISBN number. I also recently heard someone talk about an IM message, referring not to a message regarding an instant message, but to an ordinary instant message.

I’ve heard plenty of people (including myself) complain about this careless treatment of acronyms, including a character in the comic strip Jump Start, in the installment from December 17, 2002:

Son: There’s an ATM machine next to the escalators.
Mom: Really? An automated teller machine machine?
Son: Mom, you’re repeating yourself.
Mom: I am?
Son: You said the word “machine” twice.
Mom: You’re the one who called it an “ATM machine.” “Machine” is what the “M” stands for in the acronym “ATM.”
Son: Just enter your PIN number, willya?
Mom: Personal identification number number?

But we must go beyond mere complaining, and ask ourselves, “Why?” OK, OK, we linguists must go beyond mere complaining, etc., but anyway: Why is it that speakers tend to redundantly expand these acronyms? Why don’t we ever hear about AT machines, PI numbers, or I-messages? (Actually, I have heard about the last item, but only in anger-management contexts.) Right now, I don't know, so instead, I’ll ask “When?” When, exactly, are acronyms subject to this kind of expansion? The four data points so far have several things in common:

1. Phonetic: They all end in a nasal consonant (M or N).
   
2. Syntactic: They are all common nouns (not proper nouns, such as FBI).
   
3. Semantic: The final letter stands for the “main” noun (which linguists refer to as the head noun). That is, an ATM is a kind of Machine; PINs, VINs, and ISBNs are kinds of Numbers; and an IM is a kind of Message.
   

So far, then, any combination of these facts could be the magic combination that correlates with a tendency to be redundantly expanded. Let’s check them one by one.

Phonetic: Are there redundantly expanded acronyms ending in letters other than M or N? The closest I can think of is scuba gear, which isn’t quite an example of what we’re looking for (it would be if people called it scuba apparatus). When Dad worked at a refinery, there was a device technically known as the Fluidized Catalytic Cracking Unit, or FCCU. Does anyone ever call this an FCCU unit? I don’t know; all I know is what Dad and his coworkers called it, which I won’t write here out of respect for the high standards of Glen’s blog. What about OR room, or ER room? I haven’t heard these, but I could imagine them being out there.

Syntactic: Are there redundantly expanded acronyms that are parts of speech other than common nouns? I can’t think of any. You’d better get here PDQ quick sounds pretty bad to me (i.e., even worse than ATM machine, etc.).

Semantic: Are there redundantly expanded acronyms whose head noun is abbreviated by a letter other than the last one? Has anyone ever heard someone talk about the OMB office, or the BLM bureau? For a better comparison, I should find similar acronyms that aren’t proper nouns, though. Let’s see … OK, how about ETA time? I’ve never heard it, but I suppose it could be out there.

My working hypothesis, then, is that redundant acronym expansion (RAE for short; “RAE expansion” for medium) happens only for acronyms that are nouns, and whose head noun is abbreviated by the final letter. I imagine there are further restrictions, too. Even better than being able to say “RAE occurs only under conditions X, Y, and Z,” would be to be able to say, “… and always under these conditions (for speakers who permit RAE).” I’m nowhere near that point, though. Submissions of acronyms that have undergone RAE are welcomed, as are submissions of acronyms that in your personal opinion could not undergo RAE.