We all know that the cardinal and ordinal numbers 4 and 4th are spelled ‘four’ and “fourth” respectively. Then we have 14 and 14th which are spelled “fourteen” and “fourteenth”. Yet the numbers 40 and 40th are spelled without the letter ‘u’, as in “forty” and “fortieth”.

It is said that Old English and Middle English spelling was phonetic but over time letters were either added or removed from words to resemble more closely their Latin origins; e.g., dette was replaced by ‘debt’ (L. debitum). And as customs in pronunciation changed so did the spelling, for instance ‘drink’ used to be drincan in Old English.

With that in mind, it's not a surprise when the letter ‘u’ in fourty became silent, it was dropped.

Merriam-Webster says

The logical Middle English relic fourty, …, lasted until the 18th century, when for reasons unknown it fell out of use. Sometimes that's just how it goes in English.

However, the same spelling change did not happen to “four” /fɔː/, and "fourteen" /fɔːˈtiːn/ or /ˈfɔːtiːn/, despite the ‘u’ being also silent.

Is there an explanation for this discrepancy? Why did the spelling change for “forty“ but not for numbers “four” and "fourteen”?

  • I think at least some of what you're asking about here is covered by the ELU question Why did the letter “o” disappear in the word “pronunciation”? Sep 20, 2020 at 15:40
  • 1
    Otto Jespersen seems to have explained it in his book A Modern English Grammar on Historical Principles, though he doesn't say anything about its spelling. Also see Merriam-Webster's article "Fourty or Forty?". Neither of them cuts the mustard.
    – Void
    Sep 20, 2020 at 17:53
  • I guess nobody knows exactly. The GVS is too complex.
    – user17814
    Sep 21, 2020 at 12:34
  • Your question is good. It made me think why the sound of h is dropped for the word "hour" and I checked the paid Merriam and it says, "Middle English our, hour, from Old French ore, ure, hore, hure, heure, from Late Latin & Latin; Late Latin hora canonical hour, from Latin, season of the year, time of day, part of the day, hour, from Greek hōra — more at year". I thought just trying to "solve" it is fruitless.
    – user17814
    Sep 21, 2020 at 12:53

3 Answers 3


It's just yet another weird illogical piece of English spelling. No logic to it at all.

In Anglo Saxon we had 4=feower 40=feowerti. Here you can see the "w" that became reduced to "u" in the modern spelling of four and absent from forty. Perhaps this follows the Northumbrian dialect "feuortig" in which the u/w has switched places with the "o". Perhaps it was one publisher in the 17th century that standarised on forty and the 18th century dictionary writers followed that lead. It is probably just random.

Det ->debt is special case. Generally the spellings became fixed, but the pronucniations changed. It is easier to understand Middle English when spoken than when written (for me anyway).


Two thoughts:

  • "For" would look the same as the preposition "for", so would potentially be a little confusing in a way that "forty" isn't.
  • Some speakers apparently say "four" differently from the "for-" of "forty". The Longman Pronunciation Dictionary by J. C. Wells gives only /fɔ:/ for British English but both /fɔ:r/ and /foʊr/ for American English. The OED specifies /fɔ(ə)r/ for American English. However, Wells doesn't give /oʊ/ as an option in the word "forty" (which he does for "fourteen"), nor does the OED include an optional schwa in "forty" (although the OED doesn't include an /r/ in "forty" either, so might have forgotten to include an American pronunciation at all in that entry).

It seems therefore that the "horse"/"hoarse" distinction that some speakers observe may involve different pronunciations for the vowels in "four" and "forty". This is also implied by the discussion at https://wordagents.com/forty-or-fourty/ .

  • I understand in writing "four" would avoid any possible ambiguity, but what about fourteen? And in speech the words "two", "to" and "too" are pronounced the same, as is the vowel sound in "for" and "four" with or without the rhotic R ending.
    – Mari-Lou A
    Sep 20, 2020 at 12:59
  • (1) The fact that "to" and "two" are pronounced the same (except when "to" has its weak form /tə/), but are written differently, seems an argument in support of, rather than against, having a similar distinction between "for" and "four". I agree that it doesn't apply to "fourteen". (2) But as per my second point, "for" and "four" aren't necessarily pronounced the same. Some speakers pronounce "four" with a diphthong /foʊr/ - they wouldn't pronounce "for" that way, nor (apparently) "forty".
    – rjpond
    Sep 20, 2020 at 13:05
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    I agree with this answer. It's possible that the scholars of Middle/ Old English elided the 'u' so as to avoid horse-hoarse merger but who knows... I didn't find any good explanation but I guess (wild guess) the 'u' got removed from 'fourty' because at some point, the pronunciation changed and scholars of that time elided the 'u' from 'fourty'. You could as well ask why there's an O in 'pronounce' but there's no O in 'pronunciation'.
    – Void
    Sep 20, 2020 at 13:11
  • @Wistful I was thinking more along the lines of AmEng spelling e.g. color, humor*, favor* etc. all words that have dropped the letter "u". Whereas I pronounce the second syllable in "pronounce" and pronunciation quite differently, the former has /naʊns/ but the latter has a /nʌn/ sound.
    – Mari-Lou A
    Sep 20, 2020 at 13:41
  • 1
    There are definitely some BrE dialects where "four" has nearly 2 syllables, but the "for" in forty does not.
    – xorsyst
    Oct 29, 2020 at 11:47

Interestingly, forty is spelt differently from four and fourteen. There are good phonological explanations for this quirk. IIRC, at the close of the middle English period, forty had a diphthong [ou] which in Early Modern English merged with [o:]. [o:] was developed from middle English [ɔ:]. At that time, forty had two syllables due to which [o:] was shortened to [o] and manifested itself in the spelling; forty. Oddly enough, four and fourteen didn't undergo that shortening for some reasons. You may know that English spelling was standardised in middle English so it reflects that change.

In the seventeenth century [o] was lowered and lengthened before /‑r/ to [ɔː] coalescing in this position with the long vowel which only lowered before /‑r/ (i.e. to [ɔː]).

Here's what Eilert Ekwall has to say:

Before r-groups ME ō, ū have mostly been preserved as long vowels, EModE [u:], PresE [ɔ:], as in board, hoard, forth, mourn; a short vowel, however, in word, EModE [wurd], whence [wəːd]. A long vowel has been retained in fourth, fourteen, with EModE [oːu]; forty, on the other hand, had [ɔː] in EModE, whence through later lengthening [ɔː]. In words like earth, learn, beard, earn the pronunciation varied much in earlier ModE between long and short

("A history of modern English sounds and morphology" (page 12))

  • Hi, welcome to ELL! Thanks for this answer.
    – Eddie Kal
    Dec 24, 2020 at 9:22

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