I almost hesitate to ask this, because it is hard to believe no one else asked it; but it isn't showing up in the "similar titles" list.

What is special about 'C' that switches the 'IE' immediately following it?

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    It's not true. They don't teach that at schools (over here in the UK) any more. Jul 15, 2011 at 15:24
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    The rule is not what you state. It is that when you have an /iː/ sound and must choose between the the two spelling “ie” and “ei”, *then and only then is it “ i before e except after c”. It has never ever ever been a general rule without the conditions I gave. The chief exception is weird.
    – tchrist
    Feb 21, 2012 at 21:27
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    The rule is rather unscientific. Jan 18, 2014 at 18:10
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    There's an episode of QI why Stephen Fry says that they don't teach it in schools anymore, and goes on about how the rule is wrong. They then list loads of examples of "ei" appearing after something other than a C, and they all either have the wrong sound or are foreign or both. It is infuriating.
    – Rupe
    Jun 13, 2014 at 20:13
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    @Rupe You can't forget about that feisty heist on weird beige foreign neighbors. And in the same vein, eight leisurely atheists' weighty sleigh ceilings either conceive heifers, conceitedly seizing obeisance (albeit forfeiting their heirloom reign), or heighten caffeinated protein (feinting a plebeian receipt).
    – Daniel
    Jul 1, 2014 at 22:05

4 Answers 4


Basically, English vocabulary is a mix of mostly proto-Germanic and proto-French, the languages in use by the Saxons and Normans respectively during the Norman invasion and occupation of the British isles. To this was added hefty dashes of classical Latin and Greek, and then Romanizations of words from all over as words were borrowed from British colonies and from American immigrants.

Anyway, in German, the rule (when explained to native English speakers) is that when I meets E, the second vowel is the sound of the pair, and is sounded long. So, EI is sounded like "aye", and IE is "ee".

In French, it's not so simple, but usually, IE is "ee" and EI is "ey" (long a). It's really closer in most cases to "eh", but that's far more open than the "eu" or schwa sound that is an unattended "e".

So, from both these languages, when "ie" is a monopthong (or "digraph"; two letters making one sound), it's usually "ee", and then "ei" is normally given its French pronunciation of long "a" or similar (as in "neighbor" or "weigh"), with a few exceptions usually given the Germanic long I.

The mixing in of C also appears French; the word "deceive", for instance, is rooted in the old French deceivre, identical in meaning. The French would use their normal long "a" pronunciation for "ei", but in the transition to modern English it became "ee". Words such as "receive" and "ceiling" also have ties to French, though sometimes, as with "ceiling", the spelling in the other language isn't anywhere close.

So, that's the origin of the rule; when I and E meet to say "ee", both of English's parent languages usually indicate "ie". The "except after c" is because we Anglos butcher the French contribution so badly, and the "or when sounded as 'ay'" is for the rare occasions we get it right.

Now for why it's not such a great rule:

The largest section of exceptions to the full rule, "I before E, except after C, or when sounded like 'ay', as in 'neighbor' or 'weigh'", is when "ie" or "ei" is not a digraph, but instead a diphthong. The word "science", and its various derived words, do not have their "ie" pronounced as long "e" OR long a; it's two elisioned sounds, "eye-eh". Same with "conscience". Similarly, words like "deity" are pronounced "ey-ih", again pronouncing each letter. Most of these are from base Latin or Greek roots instead of French/German.

The second biggest group of exceptions are words that have evolved multiple acceptable pronunciations: "either" can be pronounced "ee-ther" or "eye-ther" depending on dialect. Similarly, "neither", "geisha", "leisure", "weird", etc. all have multiple acceptable pronunciations of the digraph.

Recent additions to the English language, borrowed from other languages, are likely to also be exceptions to the rule; "gneiss" for instance.

Finally, the plural form of a word ending in "cy" such as "fancy" or fluency" is always spelled with "cie" ("fancies", "fluencies").

  • 6
    Weird can be pronounced w-eye-rd? Odd. +1 for an excellent answer.
    – MrHen
    Jul 15, 2011 at 4:37
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    Geisha can be pronounced geesha? I'm shocked! O_O
    – deceze
    Jul 15, 2011 at 5:08
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    @MrHen: Actually, the alternate pronunciation other that "weerd" would be "wihrd", using an "i" as in "pit". This word comes from the Celtic "weir" which is pronounced "wihr".
    – KeithS
    Jul 15, 2011 at 15:15
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    You’ve made if far too complicated. The rule is that when and only when something is sounded /iː/ and you must choose between “ie” and “ei”, then and only then is the rule to spell it “i before e except after c”, with the chiefmost exception being weird. The -cy > -cies inflection is a good catch, though.
    – tchrist
    Feb 21, 2012 at 21:30
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    @tchrist: The rule only applies in stressed syllables. When the letters ei/ie are used to represent stressed /i:/, ei is used if the preceding letter is c, and ie otherwise (except ‘weir’ and ‘weird’ and perhaps a few others here and there as well). Jan 18, 2014 at 4:32

Well, the rule isn't true at all. There are more exceptions to the rule than that follow it.

According to QI, 923 words have cie (against the rule), 23 times more than cei (following the rule).

  • 1
    Well, I know.. I was being a little bit facetious. But still, they don't stuff our young kids' brains enough. Kids have sponges in their heads. Jul 15, 2011 at 2:10
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    But that's not what the rule says. It says it's always "ie" not "ei", but that the rule doesn't hold after "c". It doesn't say "i before e but the opposite way round after c". So it has its limitations (though fewer if you use the version "i" before "e", except after "c", when the sound is "ee" that is common in the UK), but that's not one of them.
    – psmears
    Jul 15, 2011 at 8:35
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    +1 (++) - So glad to see this answer. One thing you don't mention is that the "full" text of the rule has an exception and an exception to the exception tacked on in a desperate attempt to make the rule valid. Even when you do that, the most common i & e word in English (their) doesn't follow the rule. I misspelled "their" for decades because I had that stupid non-rule "rule" beat into me as a kid.
    – T.E.D.
    Jul 15, 2011 at 17:49
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    This answer says nothing about whether this is a good rule of thumb because it completely ignores (a) the probability distribution of words (i.e. maybe words that break the rule are less common than those that follow it) and (b) the number of words that contain "ie"/"ei" not following a "c". Jul 16, 2011 at 0:25
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    St Stephen simply got it wrong. It’s much simpler than this. See my other comments.
    – tchrist
    Feb 21, 2012 at 21:31

There are actually only 5 exceptions if you apply the right conditions to the rule.

"I" before "E" except after "C" or when sounded as "A" as in neighbor or weigh.

The rule apples to words with a long E sound (piece, believe) or long A sound (eight, their).

It does not apply to words in which the I and the E are pronounced as individual syllables (uglier, cuneiform, etc.).

It does not apply to chemical names (codeine, protein, caffeine).

It does not apply to words with a long I or short I sound (height, forfeit, etc.)

It does not apply to words in which the preceding "c" is pronounced as "sh" or "ch" (ancient, efficiency, etc.).

Applying those rules, there are 5 exceptions: weird, seize, leisure, either, and neither.

Either and neither are often pronounced with the long I sound, in which case the rule would not apply anyway.

It is actually a very simple, practical rule. Students need to learn the conditions of the rule and the five exceptions. Soon, they will be on their way to spelling mastery.


There is nothing special about the letter <c> in particular that makes it affect the spelling of a following digraph. "I before e except after c" is not really a rule in the sense of a systematic principle of English spelling; rather, it's a mnemonic for remembering that the sound /iː/ is irregularly spelled as <ei> in one root that happens to show up in a number of relatively common words: receive, perceive, conceive, deceive, receipt, conceit, deceit. These words all have <c> before the <ei> because they are all related to each other (although they are also related to some words spelled with <cept>, where the vowel is pronounced and spelled differently). The unrelated word ceiling also happens to have <c> before <ei> = /iː/. And that's basically the entire basis of the mnemonic. If we didn't happen to have words derived from the -ceive/-cei(p)- root, or if the words derived from this root had gotten different standardized spellings (e.g. with <ea> instead of <ei>: spellings like <conceave> were in fact used in some Middle English texts) then we presumably wouldn't have the mnemonic.

As critics of the "rule" are fond of pointing out, there are a few more words where /iː/ is written <ei>, like seize, and for some speakers weird (since the vowel in this word is r-controlled, different speakers identify it with different vowel phonemes). This use of the <ei> digraph comes from French and isn't in principle restricted to occuring after <c>. There just aren't many examples of <ei> = /iː/ after other letters because <ei> is uncommon in general as a spelling for /iː/ in present-day English. The use of <ei> as a digraph for a sound like /i/ or /iː/ may be more common in other times or places: e.g. in Scots spellings like <deid> (= standard English "dead").

It's not a matter of <c> causing an immediately following <ie> digraph to "switch" or anything like that. As the comments and other answers mention, there are many words are written with <cie>, with various pronunciations. In particular, <cie> is common in inflected or derived forms of words ending in <cy>, because of the tendency to replace <y> with <ie> in certain contexts, such as in plural forms ending in -ies or verb forms ending in -ies or -ied (a "rule" that is actually productive and applies to a great many words, unlike the "i before e except after c" mnemonic).

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