I often catch myself trying to write ?explaination, phonetically spelling the word in my head. To my chagrin I get part way through and have to stop myself.

So I’m wondering why is the i dropped? I can’t think of other words ending ‑ain that take the ‑ation suffix for comparison.

  • 2
    At least you're not Ricky Ricardo, you'd be dropping the "e", too.
    – JeffSahol
    Aug 14, 2012 at 18:07
  • 4
    There are plenty of other examples of dropped/altered vowels: Explain goes to Explanation much like Exclaim goes to Exclamation, and Pronounce goes to Pronunciation, and Maintain goes to Maintenance.
    – J.R.
    Aug 14, 2012 at 19:44
  • 16
    The written word explain contains an "i". The word explain is pronounced /ɛk'splen/, with no i's. The derived noun explanation is pronounced /ɛksplə'neʃən/, with different vowels. The spelling merely attempts (in no consistent way -- which is typical of English spelling) to represent the different vowels in the pronunciation. Warning: Do Not attempt to make sense of English spelling; go for the pronunciation because that's what's important. Spelling you just have to memorize, unless you get a PhD in historical linguistics. Apr 28, 2014 at 17:59
  • 10
    For the same reason a vowel disappears from detain in detention or from ordain in ordination: because you won’t have a long vowel in an unstressed syllable.
    – tchrist
    Apr 28, 2014 at 17:59
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    John, where is the source for that pronunciation? I've never heard explain pronounced that way, it's always /ɪkˈspleɪ̯n/ or /ɛkˈspleɪ̯n/ which certainly has an "i" sound to it. The hypothetical word "explan" would be pronounced distinctly.
    – Hugh
    Apr 28, 2014 at 23:16

4 Answers 4


Expanding on ΜετάEd’s answer, the alternation between long /e:/ and short /a/ (or reduced version thereof, schwa or a mid-high vowel) is now frequent in Modern English (and harks back to the Great Vowel Shift).

So, alongside expl[e:]n ~ expl[ə]nation, you also have:

  • ex'pl[e:]n ~ expl[æ]natory
  • ins[e:]ne ~ ins[æ]nity (insane ~ insanity)
  • in[e:]ne ~ in[æ]nity (inane ~ inanity)
  • n[e:]tion ~ n[æ]tionality (nation ~ nationality)
  • [e:]ble ~ [ə]bility (able ~ ability)

As you hunched and ΜετάEd pointed out, there is an orthographic oddity to explain, in that its /e:/ sound alternates with a lax vowel, but it is, orthographically, ai. The nearest I can come to like examples is:

  • retain ~ retention (this too is an etymological oddity, examples like contend ~ contention, intend ~ intention_, and so on, would lead one to expect retend ~ retention)
  • inveigh ~ invective (where the origin of eigh is again etymologically odd, coming from invehere)

As the parenthetic comments make clear, these are as much oddities as the case you identified.


The question should be: where did that i come from.

If we look at etymonline we find the following: (emphasis mine)

explain (v.)
early 15c., from Latin explanare "to make level, smooth out;" also "to explain, make clear"

Originally explane, spelling altered by influence of plain. Also see plane (v.2). In 17c., occasionally used more literally, of the unfolding of material things: Evelyn has buds that "explain into leaves" ["Sylva, or, A discourse of forest-trees, and the propagation of timber in His Majesties dominions," 1664]. Related: Explained; explaining; explains.

So it seems that the form explane, probably pronounced much like the current version, lost its final e and to reflect the pronunciation in the spelling, an i was added.

  • 3
    Like I say, don't expect English spelling to make sense. There is immense and largely random variation in the history and use of every word in the language. And of its spelling. Apr 28, 2014 at 18:05
  • 3
    I don't expect it to make much sense, but sometimes there are - at least just below the surface - some nice factoids that can make the memorizing a bit easier to live with :)
    – oerkelens
    Apr 28, 2014 at 18:10
  • 1
    Anything that helps memorization is unmixed good, as long as you don't try to stretch it to fit everything. As for other facts and other factoids, you can get all you need in David Crystal's Cambridge Encyclopedias, of Language, and of the English Language. Apr 28, 2014 at 18:16
  • 1
    I'm a beginner... I just finished he Little book of Language :)
    – oerkelens
    Apr 28, 2014 at 18:46

OEtmD says explain was “originally explane, spelling altered by influence of plain”.¹

There have been many different ways that English words have been spelled to indicate pronunciation. The word plain, for example, has been spelled plain, plane, plaine, playn, playne, pleyn, plegn, and plen.²

Over time, spelling has become more consistent: for example, we use plain and plane, and have stopped using the others. But spelling has not been regularized to the point where every similar word uses the same spelling rule to indicate pronunciation.

There is not really a particular reason why we ended up with a particular spelling: or, rather, the reason is simply that the language evolved to be so.

  • Then why drop the "e"? ;)
    – CodeBlue
    Aug 14, 2012 at 20:17
  • Looking at examples in the OED, it seems that the word "explanation" is older (first documented use 1382) than the verb "explain" (1535).
    – Alex B.
    Aug 14, 2012 at 20:41
  • OEtmD has explain early 15C (early 1400's).
    – MetaEd
    Aug 14, 2012 at 20:43
  • 1
    Here's what Upward & Davidson 2011 say in their book, "The History of English Spelling": "More strikingly anomalous is explain, whose source, as is more apparent from the noun explanation, is the Latin explanare (Modern French expliquer ‘to explain’ derives from Latin explicare, whence also explicable); explain had the alternative form explane, but by not following the respelling of the cognate plain as plane in the 17th century, it now falsely suggests a relationship with unrelated complain (< Old French complaindre < Late Latin complangere)."
    – Alex B.
    Aug 14, 2012 at 20:46
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    Playing with Middle English corpora, I found "explane" in "Treatises of fistula in ano" written by John Arderne (1307–1392), "I may plenerly explane tham in this litel boke" (page 3, line 23).
    – Alex B.
    Aug 14, 2012 at 21:06

The Latin stem explan- of explanare is to explain in English; the stress is on the vowel a and this leads to an enlargement, a becomes ai /ei/. In explanation the stress is on the next syllable. So we might guess the spelling would be explanaition, but obviously one has kept a spelling that is conforming to the Latin noun explanation(em).

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