Today I learnt that revoke + able would make revocable. What's the reasoning for this? Are there any other examples like this?

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    the real question is: why does the K of verbs like revoke, provoke etc. turns into a c in the adjectival form?
    – user 66974
    Apr 6, 2020 at 16:52
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    I would upvote this question if you turned it into a question about why some words ending in -ke become -cable (and/or -cative), while others become -kable (or -keable). As Edwin Ashworth observes, there is a strong (and justified) bias against list request on this site—but the issue of differential ending change that you raise is interesting, especially if it turns out to be largely explicable in terms of the different language origins of the root words. (I would also change your tag from 'single-word-requests' to 'suffixes' and maybe 'orthography'.)
    – Sven Yargs
    Apr 6, 2020 at 17:09
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    This is not a question about English, but about the vagaries of English spelling. Sounds don't come from letters -- letters come from sounds. Apr 6, 2020 at 17:44
  • 3
    @JohnLawler - How are vagaries of English spelling not about English?
    – user 66974
    Apr 6, 2020 at 18:01
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    Because they don't have any relation to the English language, only to the technology for recording it, which simply piles up changes like Windows versions, all following different rules, none of which refer to the language. Apr 6, 2020 at 18:16

1 Answer 1


It's Latin vs Germanic origin.

Consider the following examples:

Likeable, unlikeable, makeable - Germanic origin

These words are of Germanic origin. And German allow 'k' in suffixed words.

On the other hand,

Revocable, invocable, provocable - Latin origin

These words are derived from Latin revocare, invocare and provocare respectively.

In Latin, they're pronounced with /k/ sound (it's obvious from the spelling - 'care', c often gives /k/ sound when it precedes 'e').

These words are anglicised to revoke, invoke and provoke.

Where did the k come from: In order to maintain the /k/ sound (which is in the original pronunciation 'care'), the 'ce' was changed to 'ke'. Because if it were written as 'revoce' it would be pronounced with /s/ sound rather than the original /k/ sound.

Hachi's comment:

The real question is: why does the K of verbs like revoke, provoke etc. turns into a c in the adjectival form?

When a suffix is added to revoke, the 'k' changes to 'c' because it's not allowed in Latin (and Latin words in English) to have 'k' in suffixed words. Latin does not allow the letter 'k' at all.

Therefore, revoke + able -> revo(_)able/ revoke + tion -> revocation ---> 'k' is not allowed, we need another letter than gives /k/ sound (original sound) before the letter 'a' - the only letter (other than 'k' because 'k' is not allowed) that gives /k/ sound before 'a' is c.

  • Revoke + able -> revocable.
  • Invoke + able -> invocable
  • Provoke + able -> provocable

However, 'notice' is also from Latin but it does not have the letter 'k' because the original pronunciation (in Latin) has /s/ sound rather than /k/ sound. In order to maintain the original sound, we write 'notice' with c sound because 'c' often gives /s/ sound when it precedes e.

Notice + able -> noticeable not noticable because it changes the original pronunciation of the base word.

Why doesn't Latin allow the letter k: Lewis and Short also have a look at Latin SE

I found another similar question but the answers there do not address the 'why'.

  • 3
    This is broadly right, but I'd quibble over some details. The forms with 'c', like revocable and vocation are mostly borrowed from French or Latin, rather than being formed in English, so they came with a 'c'. The outlier is the verb form with 'k', which has been remodelled in English, as you say, apparently to avoid the 'oce' spelling. So it's not English using 'c' instead of 'k'; it's English not changing 'c' to 'k' in those contexts. Notice is quite different because it was remodelled in French: the Latin word is notitia, which has neither 'c' nor 'k'
    – Colin Fine
    May 18, 2020 at 12:17
  • "it's not allowed in Latin (and Latin words in English) to have 'k' in suffixed words." Then why do we have "embark" and "embarkation"? Feb 2, 2022 at 21:42
  • I personally think "ka" should be written throughout Latin instead of "ca". "c" should instead use the /t͜ʃ/ phoneme everywhere as there is no letter to write that phoneme. May 3, 2022 at 22:17
  • Why does "remarkable" use "k" even though it is of Latin origin? Jun 1, 2022 at 22:02

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