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Abso-fuckin’-lutely: English Expletive Infixation

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The English Expletive Infix

If you’re a native speaker of English you’ve probably heard (and maybe used) what linguists call the “expletive infix”—that’s when you insert an emphasizing “fuckin'” right inside of another word. For example:

Examples of expletive infixation

Examples of Expletive Infixation

Since it’s “just” swearing, you might think that this process would be linguistically crude, and maybe kind of random—but in fact, expletive infixation is systematic, and requires a very precise calculation of where to put the infix (i.e. the inserted “fuckin'”). Observe, as evidence of this, how weird it sounds if you put the infix the “wrong” position, even by one syllable:

Examples of mis-placed expletive infix.

Examples of Mis-placed Expletive Infixation

There must be some kind of pattern that we all unconsciously learn and follow. But obviously no-one taught us this rule in grammar school. And most of us don’t even get to hear that many examples. Yet somehow, we all have strong, clear, and subtle, judgements about where the infix properly fits.

All of which leads to the questions for this post: (i) what the heck is this pattern that we follow? And (ii) how the heck did we learn it?

Background: The BOOM-bah Rhythm of Words (Alternating Stresses)

To understand English expletive infixation, it turns out that you first have to understand that English words have a rhythm to them. In part—though the pattern only emerges clearly in certain longer words—this rhythm consists of a series of “BOOM-buh” beats. That is: we stress (i.e. emphasize) one syllable, then de-stress the next, and so on. In the clearest cases this results in a pattern of “beats”, i.e. pairs of alternating stressed-unstressed syllables, stretching across the word.For example try saying the words below, and see if you sense the same patterns of stressed and unstressed syllables (“BOOM-buh” beats) as in the illustrations (physically, the stressed syllables “BOOM” syllables will be a little longer, and maybe a little louder):

Examples of stressed-unstressed "beats"

Examples of Stressed-Unstressed “Beats”

The rhythmic structure of words can be complicated by various factors, and we’ll look at some more complex examples shortly; but at this point you just need to be aware of two basic points:

  • Words have a rhythmic pattern to them, and
  • The “BOOM-buh” beat, i.e. a pattern based on pairs of stressed-unstressed syllables, is a basic unit of that rhythm.

It’s as if we give our words a back beat!

The Basic Solution: Don’t Break up a BOOM-bah Beat

Once we recognize that our words contain rhythmic beats, the pattern behind “fuckin'” infixation turns out to be, in itself, actually pretty simple:

  • You can put “fuckin'” between “BOOM-buh” beats. But…
  • You cannot use “fuckin'” to break up a “BOOM-buh” beat.

For example, most speakers find they cannot break up the words below at the spots marked “X” (so that we cannot infix into “Toga” at all: it consists of a single beat.). But most speakers also find that “fuckin'” is good (or at least much better) at the spots marked with the check-mark—that is, at the spaces between the beats. Try putting infixes at the marked spots, and see for yourself how it sounds!

Examples showing predicted positions where infix can (and cannot) go

Predicted Positions Where Infix Can and Cannot Go

If this account is right, then it explains why this subtly constrained process is so easy and natural to “learn”: in a way, you don’t have to learn anything at all!

That is because, long before you hear words like “fuckin'”, you have already grasped and internalized the complex and (mostly predictable) rhythmic patterns of the English language; all you’re doing, when you constrain where you put your expletive infixes, is just following the natural rhythm of your words.

The Linguistics Analysis: Don’t Break up a Foot

Linguists don’t usually use the term “BOOM-buh”, of course. They call the beats “feet”—using the name for equivalent units in poetry—with each foot consisting of one stronger (“s”) and one weaker (“w”) syllable (some feet also contain just a single syllable, depending on the word). Somewhat simplifying the structures, linguists using feet will represent the rhythm of words like in these examples:

Foot-based examples of where infix can and cannot go

Examples of where Infix Can and Cannot Go, Foot-Based Theory


As you can see, using the more precise notion of “feet”, the constraint on expletive infixation comes down to this:

  • You can put “fuckin'” between feet. But…
  • You cannot use “fuckin'” to break up a foot.

As shown by the “X”‘s and checkmarks, this more precise formulation predicts the same positions for infixation as the previous simplified “BOOM-buh” account.

And again, under the foot-based approach, infixation isn’t really something you have to “learn”: all that blocks the bad cases of “fuckin'” is that those are the cases that would break up a foot. Assuming that broken feet (which would mean crossing lines in the structure) are intrinsically ill-formed, you don’t have to learn anything special to master “fuckin'” infixation—you automatically know what to do, once you know the rythmic structure of your language.

Some Additional Cases and Notes

Primary Stress

In longer words with multiple stresses, one of the stresses (normally the last one) is especially prominent—what linguists call the “primary” stress.

If there are several stresses (hence several feet) in a word, many people find that they prefer their “fuckin'” infix before the primary stress—something to be aware of in studying the phenomenon.

Complex foot structure: un-fuckin’-believable

Not all words have a neat and simple sequence-of-BOOM-bah structures, of course. To give an example, based on independent evidence that we won’t get into here, “unbelievable” appears to have a fairly complex structure, along these lines:

Complex foot-structure example - unbelievable

Complex Foot-Structure Example

Because, in this independently motivated structure, “un-” is a separate foot, expletive infixation can appear between “un-” and the rest of the word—which explains why we say “un-fuckin’-believable”.

This particular word is also interesting, though, because it is one of the rare (but not impossible) cases where the infix occurs before an unstressed syllable. Because it separates feet, infixation usually ends up before a stressed syllable (as in all the previous examples, above), and because of this some people mistakenly think that the rule is simply (but wrongly!) put the infix goes before a stressed syllable.

Though the stress-based account will usually work as a rule of thumb, this particular word shows that it really is the foot structure that’s important.

More complex foot structure: Tata-fuckin’-magouchie:

Based again on independent evidence that we won’t get into here, it turns out that some words also have a special three-syllable s w w “sort of” foot, with a structure like the “Ta-ta-ma” unit here:

Example of complex foot "Ta-ta-ma-gouchie"

Complex Foot Example: Three-syllable “Sort-Of” Foot

Given this structure, it’s not surprising that you can say “Tatama-fuckin’-gouchie”, using the second of the two infixing spots—that’s expected, because it’s clearly between feet. What’s a little surprisingly, though, is that many speakers think it also sounds okay to infix in the first spot, i.e. to make “Tata-fuckin’-magouchie”.

What this shows is that the infix can, at least marginally, break up one of these three-syllable “sort of” feet. This is an interesting wrinkle, but it also isn’t really a problem for the foot-based account—so long as we recognize that the three-syllable pattern “ta-ta-ma” is not the same as a regular foot. In fact, it supports the foot-based analysis (as opposed to a simple “put it before the stressed syllable” account), because “Tata-fuckin’-magouchie” is another instance where the infix goes before an unstressed syllable.


This post is based very directly (though with much simplification) on the following paper (one of Dr. Dexterous’ top ten favourite papers in linguistics!):

Some of the earlier studies of expletive infixation include:

  • McCawley, James, “Where you can Shove Infixes”, (1978), in “Syllables and Segments, ed. by Alan Bell & Joan Hooper, 213-21. Amsterdam: North Holland.
  • McMillan, James, “Infixing and Interposing in English”, (1980), American Speech Vol. 55, 163-83.

The broader study of the syllables and the rhythmic structure of language is called “Metrical Phonology”, and if you want to learn more about it some seminal papers include:

  • Hayes, Bruce, “A Metrical Theory of Stress Rules” (1980). M.I.T. dissertation.
  • Kiparsky, Paul, “Metrical Structure Assignment is Cyclic” (1980). Linguistic Inquiry, Vol. 10, 421-441.
  • Lieberman, Mark and Alan Prince, “On Stress and Linguistic Rhythm” (1977). Linguistic Inquiry, Vol. 8, 249-336.
  • Prince, Alan, “A Metrical Theory for Estonian Quantity” (1980). Linguistic Inquiry, Vol. 11, 511-562.
  • Selkirk, Elisabeth, “The Role of Prosodic Categories in English Word Stress” (1980). Linguistic Inquiry, Vol. 11, 563-606.

Those papers assume a lot of pretty advanced linguistics, though, so if you are new to the field but interested in rythmic structure (in all languages), then you’ll want to start with this book:

    • Hayes, Bruce, “Metrical Stress Theory: Principles and Case Studies” (1995). University of Chicago Press.


3 Responses to Abso-fuckin’-lutely: English Expletive Infixation

  1. Judith K. Bogdanove December 10, 2014 at 3:39 pm #

    Nice article, but I believe that it’s wrong about kleptomaniacal. That word is not actually 3 BOOM-bahs. It’s one BOOM-bah KLEP-to and a second complex structure that’s actually
    bah-BOOM-bah-bah. So I believe that only one “fuckin'” may be inserted after KLEP-to…as in:


    • Dr. Dexterous December 10, 2014 at 4:59 pm #

      Thanks Judith, yes I think you are right! –DD

    • William May 25, 2015 at 12:55 am #

      Actually…kleptomaniacal is two dactylic feet (a double dactyl) KLEP to ma / NI a cal…so I think it’s actually an exception to the “don’t break a foot” rule…(also, another instance of fuckin’ infixed before an unstressed syllable)…just sayin…

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