Sunday, May 15, 2011

The Popular Prefix in- (Survey Results)

Thank you for participating in the prefix survey (641 responses). In this post, I discuss the prefix in- first. Then, I respond to the survey results.

(Click images to enlarge and/or download them.)

The prefix in- is a chameleon: It changes its color to blend in, so to speak, having four different forms, in-, im-, ir-, or il-, depending on the base or root to which it is attached. When the base or root begins with the sound /b/, /m/, or /p/, we use im-, as in imbalance, immeasurable, impolite. When the base or root begins with the sound /l/, we use il-, as in illegal, illogical, illegitimate. When the base or root begins with the the sound /r/, we use ir-, as in irregular, irreverent, irreligious. The standard form is spelled in-. These varied forms enable easy flow of smoothly blended speech, through a process called assimilation--where the final sound of the prefix is assimilated into the beginning sound of the base or root. 

The prefix in- is popular. According to The American Heritage Word Frequency Book (Carroll, Davies, & Richman, 1971) the most common prefix in school texts spanning grades 3-9 is un-, as in unbroken, unhappy, uncertain. The second-most common prefix is re-, as in reheat, reverse, rewind. The third-most common is in- (including im-, il-, ir-) meaning 'not' or 'without' as in inescapable, inedible, impossible, improbable, illegible, irreversible. (Learn more at Click the chart above to see the top 20 prefixes in school texts in grades 3-8, as ranked 40 years ago by Carroll et al. and applied to 3rd-grade research by White, Sowell, and Yanagihara (1989).

Wordle: top 20 prefixes wordleClick the Wordle graphic, illustrating the top 20 prefixes, created by educator Bob Maulucci (thanks, Bob!). There are more prefixes, also worth knowing. For example, students need to know uni-, mono-, bi-, di-, tri-, deci-, multi-, poly-, etc. 

The prefix in- is polysemous. This prefix has more than one meaning, so it is polysemous. The primary meaning is 'not' but the secondary meaning is 'in, into' or something of that nature. This secondary meaning of in- (aka im-, il-, ir-) is 7th among the 20 most common prefixes identified by Carroll et al. (1971), as shown on the chart provided. Examples of words that contain the prefix in- meaning 'in, into' are income, inlet, insightful, etc.

In some words, the prefix in- 'in, into' is not strictly necessary and is added for emphasis or intensity, as in the word incandescent, 'to glow from within'. Wouldn't *candescent* serve just as well? To learn more about the prefix in- as 'in, into', see
Such nuance aside, for the purpose of teaching school children, I think it best to show that the prefix in- has two meanings, 'not' or 'in' and four forms, in-, im-, il-, ir-, and that context helps us decide which meaning best fits the word.
The Prefix Poll (click survey to enlarge): Having considered these aspects of the prefix in-, would you change any of your responses?

The purpose of the survey was to prompt reflection through this question: "Where does the prefix denote 'not'? Click each word that applies." I sought to determine the extent to which the two meanings and four forms of the prefix in- were known. I was also curious about the relationship between semantic knowledge and morphemic knowledge. For each word, I provide a link to the word origins provided by the Online Etymology Dictionary.

inviolate: (54% of 641 voters responded correctly.) Yes, in this word the prefix in- denotes 'not'. If someone is inviolate, they have not been violated. Given that only about half the group responded positively to this item, I wonder if some did not know the word itself. If the word is not known, it is difficult to decipher which meaning of in- applies. Even though knowledge of morphology facilitates word learning, it does not replace contextualized word study.

(To learn more about inviolate or any other word, visit an excellent NEW online reference tool published by Serge Bohdjalian, called Memidex. Memidex combines information from multiple sources: dictionaries, thesauri, etymological sources, pronunciation guides in British and English, etc. It also includes about 1400 affixes.)

inestimable: (80% of 641 voters responded correctly.) Yes, in this word, the prefix denotes 'not' because if something is inestimable, it is of such great worth that its value cannot be estimated or counted. It is priceless.  The pronunciation might call to mind the word esteem (not estimate). If so, one might think the word means not *esteemable* or something of that nature. A careful look at the orthographic structure of the word, including an examination of the base and affix, would shed light on things. 

insert: (98% of voters responded correctly.) No, this word does not contain a prefix that means 'not' as virtually every participant knew. Rather, the prefix denotes 'in, within, inside'. Here, knowledge of the word itself seems to virtually deliver prefix knowledge. 

impossible: (94% of voters responded correctly.) Yes, the prefix in- denotes 'not' and the counterpart is possible. This word has an assimilated form of in- (in this case, im-) which might account for the 38 incorrect responses.  (I expected this item to be easier than the previous one, insert.)

implant:  (97% of voters responded correctly.) No, the prefix in- does not denote 'not' in this word; it denotes 'in, inside', as nearly everyone knew. Again, the assimilated prefix, spelled im- rather than in-, may explain the slight confusion.

inflammable: (30% of voters responded correctly.) No, the prefix in- does not denote 'not' in this word; it denotes 'within, inside, in.' The word flows from inflame--to burst into flames, from within, so to speak. This word is tricky; we assume in- denotes 'not' because that is the more common meaning of the prefix (Carroll et al., 1971). Because of the confusion created by this word, many combustible substances are labeled FLAMMABLE, doing away with the largely unnecessary prefix altogether.

incandescent: (70% of voters responded correctly.). No, the prefix in- does not mean 'not' in this word; it denotes intensity or emphasis, and also a slight sense of 'in, within', with the root cand meaning 'to glow'. Words derived from this root are candid, candent, candle, candelabra, the French chandelier and chandler, a candler maker.

irregardless: (A largely unanswerable question due to the lack of agreement between the morphemes and the word, or lexeme, but interesting to think about!).  This is illustrated by a comment posted under the survey:
  •  J. Chantler: You know, of course, that irregardless is not properly a word, although it is commonly used. Regardless is the correct form. If you parse the word, it is easy to see why - it doesn't work. IR not- regard to pay attention to - less, not having any - what???    
  • My response: That is why I have included the word irregardless in the survey, to prompt just this type of discussion. Thank you for doing so! I concur, except I am not sure I would say it is not "properly" a word, as anything becomes a word once used widely enough. Do you hold that if a word does not parse correctly it is not properly a word? Would that make the morpheme more weighty than the word?
(For rich discussion of irregardless, read Michael Quinion's World Wide Words.)

intact: (7% of voters responded correctly.) This is tricky if you do not know what the root means. Yes, the prefix in- does indeed denote 'not' in this word. The root tact is Latin for 'to touch' as in tactile, so intact might be paraphrased as "not touched, untouched," etc.

impound: (94% of voters responded correctly.) No, the prefix in- does not denote 'not' in this word; it denotes 'in, inside', as in locking the dog in the pound.  Here we have the assimilated form of in-, spelled im-, because the base (pound) begins with the sound /p/. If impound denotes to place an animal in the pound, how do we say "release from the pound?" Expound?? Nope. Depound???

So, there we have it. Interesting and promising results! Thanks for participating!

Application: Beginning in primary grades, with easy words and the most common prefixes, students need to engage in word study that coordinates sounds, spellings, morphemes, and semantics, with context (Berninger, Abbott, Nagy, & Carlisle, 2010). Teachers might begin with some explicit instruction followed by interactive word sorting, word summing, and word building, with a partner. For modeling, activities and ideas, see posts by Pete Bowers, Geri Marshall Mohler, or Marcia Henry. Also, scroll through See Spot for videos, morphemic flip books, etc.

Comments are welcome.


Berninger, V. W., Abbott, R. D., Nagy, W., & Carlisle, J. (2010). Growth in phonological, orthographic, and morphological awareness in grades 1 to 6. Journal of Psycholinguistic Research, 39(2), 141-163.

Carroll, J.B., Davies, P., & Richman, B. (1971). The American Heritage word frequency book. Boston: Houghton Mifflin.

White, T.G., Sowell, J., & Yanagihara, A. (1989). Teaching elementary students to use word part clues. The Reading Teacher, 42, 302-308.


  1. Interesting discussion here! I couldn't resist commenting on a couple of points.
    Prefixes that assimilate into different forms are very rich topics for investigation with students. When I run into a word like IMPOSSIBLE with students and they wonder about the prefix IM- it's a great time to collect words with this prefix and the IN- to introduce the idea of assimilated prefixes.

    If I point out that IN- is the default form of the prefix, and that we use -IM- before bases or stems beginning with /b/, /m/, or /p/, the immediate (IM+MEDI+ATE) and reasonable question from kids is why? Paying attention to how we physically make these initial phonemes, makes sense of this convention.

    If you pay attention to what aour lips are doing at the beginning of saying the words BALANCE, MORAL, and POLITE, the answer will soon be clear. It's hard to manipulate your mouth from saying /n/to saying /b/, /m/ or /p/. Assimilating the IN- to into IM-, however, leaves our lips in exactly the same place at the end of pronouncing the prefix, and the beginning of pronouncing the base or stem. So we get IMBALANCE, IMMORAL and IMPOLITE.

    It's so helpful for learners to see that the choice of when to use IN- or IM- is not a random rule to memorize, but that it is based on the physicality of saying these words. Having investigated the reason for the IM- form of the IN- prefix, the IL- and IR- forms are easy to make sense of too!

    It was learning about the physical aspect of assimilated suffixes that finally helped me understand the structure of the word SUF+FIX. Just start saying *SUBFIX a few times quickly, and you'll see how quickly the /b/ assimilates into the first phoneme of the base FIX! Before that it always bugged me that PREFIX had one F but SUFFIX has two.

    Another real value of learning about assimilated prefixes is that it helps guide our morphological analysis. Once you know about this convention, you start to see that the same letter twice in a row near the beginning of a word is a very likely sign of a morphemic boundary. Consider: ACCEPT, IMMUNE, ATTRACT, SUCCESS, SUGGEST, SYLLABLE, DIFFER...
    Perhaps knowing that the repeated letters are likely signals of a morpheme boundary will spark some investigations of the bound bases (and one free base) in this list.

    Finally, I must concur with Susan's assessment that IRREGARDLESS is "properly" considered a word. If it is used and understood by speakers of English, it's a word. The other point to consider here is that we shouldn't assume that the IR- is used for 'not', in this word. Susan points out that this suffix can also be used simply as an 'intensifier'. Perhaps this is the semantic force of the IR- in IRREGARDLESS.

    I am happy to admit that this suggestion counters what my Oxford says about this word.

    "USAGE Irregardless, with its illogical negative prefix..."

    A deeper look into the evidence from various references could well convince me of a better explanation of this spelling than I have offerd here. But I'm not willing to abandon a hypothesis just because one dictionary contradicts it. After all, this same dictionary uses the words RELATION and COMPLETION as examples of words using a -TION suffix!

    Sorry, this is such a rich topic, I couldn't resist a long comment!

  2. Pete, with your excellent commentary, the topic of assimilated prefixes has been more thoroughly addressed, at least for K-12 purposes. I appreciate your additional discussion, as the post itself was at max length.

    Like you, I was also excited when I first learned that the prefix suf- in suffix is actually an assimilated form of sub-, and this is true for support, too (sup- is a variation of sub-).

    Your idea that the ir- in irregardless is more for emphasis (opposed to meaning 'not') is something I had not considered, but you could be onto something. Intriguing.


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