I've noticed that modern English seems to have a very strong bias at the end of verbs towards the spelling "-ill" (i.e. with a double "l") instead of "-(consonant)-il". The overwhelming majority of such verbs (like to will, to kill, to mill, to fill, to spill, to grill, etc) are spelled with double "l". The only exception I could find so far is to bedevil.

Why is that? Is that related to some sort of etymology that shaped these verbs, or some other process like spelling reform?

I've tried to do some research and so far found that there's quite a few of non-verbs which end with "-(consonant)-il": anvil, basil, devil (which in fact brings to bedevil), council, daffodil, evil, stencil, tendril, nostril, until, vigil, pencil, etc.

Their origins seem to be different (Latin, Ancient Greek, Proto-Germanic => Old English => English path, etc), but the majority of them is of Ancient Latin / Greek origin:

  • usually a noun was ending in "-elus" or "-ilus" in Ancient Latin ("-ελος" or "-υλος" in Greek),
  • then it was converted to "-illus" in Medieval Latin,
  • then it lost "-us" ending in transition to Middle English, making it up to "-ill",
  • then it lost second "l" in modern English, making it up to "-il".

The process for "-ill" verbs seems to be similar, but somehow ends up differently, for example, for to mill:

  • classical Latin "mola" / vulgar Latin "molinus" / Greek "μυλο"
  • Proto-Germanic "*mulīnō" or "*mulīnaz"
  • Old English "mylen"
  • Middle English "mille" (double "l" appeared!)
  • modern English "mill" (double "l" wasn't abridged from Middle English)

It seems that losing double "l" is in fact a fairly modern invention: in fact, Middle English tends to spell most of "(consonant)-il" with double "l" and "-e" or "-en" ending, and then some transition happened in a few past centuries. Am I on the right track? Can I read somewhere about these reforms?

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    Is it just a coincidence that all your examples with a single l have two syllables, while the double ll goes with a single syllable? – Barmar May 20 '15 at 15:44
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    I would also have guessed it was dependent on the length of the word: Single syllable words using double-L and longer words, using single, in step with tilluntil and fullwonderful – Born2Smile Mar 14 '16 at 14:58
  • A word that ends in -il never ends in two l's. – Greg Lee Mar 17 '16 at 13:35
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    Surely this has nothing to do with middle English. The choices between single and double l were not made until very recently. In early modern English, untill was common. Even today, we haven't all agreed on fulfill or fulfil. – phoog Mar 18 '16 at 3:58

I don't think it has to do with them being verbs, and for the most part, I also don't think it has to do with the etymology. I think it mainly has to do with the stress patterns of these words.

The tendency I see is that the letter L is generally doubled after a stressed short vowel, and not doubled after an unstressed vowel. Historically, there has been a lot of variation in the spelling of words like this. Based on etymologies that I have looked up, I would say there is little to no etymological significance to the use of a single L vs. a double L at the ends of words. It's just an oddity of our modern spelling system. (Another relevant question about double L: Why is there a double "ll" in "bell"?)

Here are some actual examples: mill (as you've found out, it comes from Old English mylen), small (comes from Old English smæl), skill (comes from Middle English skele, scele, skile, skyle, from Old Norse skil), dill (from Old English dili, dile, dyle). On the other hand, metal comes from Latin metallum with a double L (although the French spelling metal may have also played a role, as French seems to have been an intermediary in the transmission of this word). I have some more examples of words like metal in my answer here: Adding an L when appending an -ium suffix to a word? (Metallium vs. Metalium)

Monosyllabic content words always end in a stressed syllable, and polysyllabic verbs are more likely than nouns to end in a stressed syllable. These two factors are probably why it seemed to you that this was related to part of speech.

There are many nouns that end in "-ill," especially monosyllables such as bill, hill, sill, and frill. Adjectives such as still can also have this spelling.

There are also verbs that end in "-il." Aside from bedevil, there are cavil, imperil, stencil, fulfil (British spelling; Americans use fulfill). However, it does seem to be true that fewer verbs than nouns end in "-il."

What is the etymology of words that end in -il?

It's worth noting that there aren't that a huge amount of words in total that end in -(consonant)-il."

As you've found, many of them are derived from Latin nouns ending in -illus, -illa or -illum. When Latin nouns are taken into English, final -us, -a and -um are often simply removed, which explains how we get English nouns ending -ill or -il.

Latin verbs, however, are usually borrowed in a more complicated fashion. For complicated historical reasons, Latinate verbs in English are generally derived from the past participle form of the Latin verb. Latin past participles generally have a dental suffix (usually t) that is retained in the derived English verb. So for example, the Latin verb inficio corresponds to the English verb infect. In regular verbs of the first declension (the most common type) this dental suffix is preceded by the vowel a. So Latin verbs containing -ill- have generally been borrowed as English verbs ending in -illate. (For example, scintillate comes from Latin scintillare). That might be a contributing factor to the relative rarity of verbs ending in "-il."

There are various other sources for words ending with "-il." In most cases, the modern spelling with "il" is fairly straightforward based on the etymology.

However, there are a handful of words that seem to have acquired the spelling "-il" for unclear reasons. Here's what I mean: devil (Old English deofol), evil (from Old English yfel), weevil (Old English wifel), stencil (earlier spelled stancel; interestingly, the Oxford English dictionary says that the noun is derived from the verb). I don't know how to explain these.

  • I still think still is most commonly an adverb, not an adjective — at least until you decide to further still an already still still that’s still making too much noise to count as a dead-still still. – tchrist Sep 17 '19 at 2:22

You should also check Samuel Johnson's dictionary. He is responsible for setting in concrete the spelling of many modern English words. There was much more variety in spelling before his dictionary was published.


I think it has to do with the Norman conquest, and the fact that they highly influenced orthography. Probably some "l"s were dropped depending on stress, or more likely, they were Old French borrowings and the Normans spelt words like "devil" how they were in Old French, how they "should" have been spelled.

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    Unlikely. The use of double letters did had not settled down even by the early modern English period. In the early 1600's, untill was common. – phoog Mar 18 '16 at 3:55

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