First of all, "threepenny" is a British word meaning "costing or worth three pence". It's quite an uncommon word. If you haven't heard it before, I'm pretty sure you would pronounce it the way "three" and "penny" are pronounced separately, that is, THREE.PENNY or in IPA */ˈθriːpɛni/.

Instinctively, the word is made up of three and penny. But here is a surprise (if you haven't come across it before): "threepenny" is pronounced as THREP.NI, IPA: /ˈθrɛp(ə)ni/ at least in British English.

Why is this so? I know English spelling and pronunciation don't go hand in hand but is there any reason "threepenny" is pronounced that way? It's kind of surprising.

Would love to know about it.

Edit: I really apologize for writing do instead of don't. It is very embarrassing.

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    I doubt any Brit younger than 45 would even remember its existence nor its value, and you certainly never hear it spoken. Where did you come across this term?
    – Mari-Lou A
    Commented Nov 28, 2020 at 12:24
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    @Mari-Lou and a different pronunciation under thruppence. Commented Nov 28, 2020 at 12:28
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    I was born in 1980 England and thrupenny was a term I've only heard used in a historical context (the thrupenny bit went out of circulation in 1970). It was common when I was younger to call a 2p coin, or just the price 2p, tuppence, but far less so now. In England its most usual to say "2p" or "3p".
    – John Davis
    Commented Nov 28, 2020 at 20:27
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    Because the people poor enough to use them were ill-bred peasants who don't speak proper like what we does.
    – Richard
    Commented Nov 28, 2020 at 23:53
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    Thrupny (not even an E as in ThrupEnny ). There is simply no other way to pronounce it
    – Mawg
    Commented Nov 29, 2020 at 18:30

3 Answers 3



I don't know how it was pronounced in the past, but it must have been /ˈθriː.pɛ.ni/ (THREE.PE.NI) at some point, which is a three-syllable word having a 'tense' vowel in its first syllable, meaning it's a prime candidate for Trisyllabic Laxing. It's a process whereby a long vowel/diphthong is shortened if two or more syllables follow:

  • */ˈθriː.pɛ.ni/ → /ˈθrɛ.pɛ.ni/ [because we know that /iː/ becomes /ɛ/ when syllables follow]

After that, the vowel /ɛ/ in the second syllable became /ə/ and syncopated (dropped) eventually so we got /ˈθrɛp.ni/.

(I have expounded on Trisyllabic Laxing in this answer to a question asking "Why are “south” and “southern” pronounced with different vowels?", but I'll just discuss it briefly here.)


Trisyllabic Laxing

Trisyllabic Laxing a process whereby a tense vowel (long vowel or a diphthong) is laxed (shortened) if two (or more) syllables follow. As we add syllables to the base of a word in English, we tend to reduce the length of the vowel in the base. If a syllable having tense vowel is followed by two or more syllables, the tense vowel often becomes lax.

At one point, this rule applied to all relevant cases; it was therefore purely a phonological rule, a constraint upon what was pronounceable in English. Later on, it ceased to be a part of English phonology, however, its remnants are still highly visible in Modern English.


  • insane /ɪnˈsn/ → insanity /ɪnˈsæn.ə.ti/
  • serene /səˈrn/ → serenity /səˈrɛ.nə.ti/
  • divine /dɪˈvn/ → divinity /dɪˈvɪ.nə.ti/

There was a fairly regular pattern of the short and long vowels in corresponding pairs.

Relationship between [iː] and [ɛ]

The FLEECE vowel [iː] has a systematic relationship with the DRESS vowel [ɛ]. The vowel [iː] in the base often shortened to [ɛ] as syllables were added to the base of a word.

This relationship is reflected in serene - serenity and brief - brevity, therefore you see the vowel [iː] in serene and brief, but [ɛ] in serenity and brevity because the tense vowel is followed by two (or more) syllables now.

Laxing of the vowel in the first syllable of threepenny

The same thing happened to threepenny:

  • /ˈθr.pɛ.ni/ → /ˈθrɛ.pɛ.ni/

the tense vowel [iː] was followed by two syllables, therefore it got shortened to [ɛ] (by Trisyllabic Laxing rule).

By contrast, the tense vowel in threefold didn't get laxed because it has always been disyllabic (two-syllable) word, and for Trisyllabic Laxing to take place, we need at least three syllables.

  • Threefold → /ˈθriːfəʊld/, not */ˈθrɛfəʊld/

Weakening of the vowel in the second syllable of threepenny

OK, the first syllable is clear now, but what about the second syllable? Why is the vowel in the second syllable further reduced (/ˈθrɛp(ə)ni/)?

It's because the second syllable has no primary stress. And as we know, unstressed syllables often get reduced to schwa hence,

  • /ˈθrɛ.pɛ.ni/ → /ˈθrɛpəni/.

Most people further reduce it to /ˈθrɛp.ni/ because there's a tendency to drop the unstressed vowel when it immediately follows a stressed syllable (as in choc.late, av.rage, cam.ra for 'some' people).

Some people also pronounce it with [ʌ] in the first syllable, but it seems to be a later change or it may be dialectal.

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    I would note that there is also a tendency for schwa followed by a continuous consonant (one that can be held) to be reduced to just a lengthening of that consonant, treating it as a syllabic consonant. This often leads to a further reduction where the consonant becomes normal length again, removing the syllable entirely.
    – trlkly
    Commented Nov 28, 2020 at 19:49
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    @trlkly: Spot on! I wanted to explain that as well, but it would further confuse the OP, so I didn't. (I explained that yesterday in another answer)
    – Void
    Commented Nov 28, 2020 at 19:52
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    This is a brilliant post, but is ELL.SE the right place for the answer (and by extension, the question)? This seems more like something graduate students in linguistics would chew on for a paper thesis than someone learning English could make use of. Commented Nov 29, 2020 at 12:50
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    I very much like the trisyllabic laxing answer. That said, I'm reminded of the words gunwhale, boatswain, and less so forecastle. The last of those seems like it could have become laxed in its trisyllabicness, less so the first one and perhaps the second but perhaps not. I only mention those because their pronunciations seem to be abbreviated and "softened" (my word) in a similar way to threepenny, and perhaps by the same English-speaking subculture. Could there be more to threepenny's pronunciation than what is in this answer? Commented Nov 29, 2020 at 22:17
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    @user1717828 You make a good point, and at the same time, when I have worked on learning other languages, I've found no information or trivial-seeming detail to be completely unhelpful. I can only imagine a particular challenge it must be for English learners to have to confront the startling differences in British versus American English, and IMHO this question sits in that space. I've never heard an American say /ˈθrɛp.ni/ or anything other than /ˈθriː.pɛ.ni/ when discussing The Threepenny Opera (the only situation where an American would say the word in the first place). Commented Nov 29, 2020 at 22:24

I grew up with the 12-sided 3d coin. We did not call it "threepence" but "thruppence" with the u pronounced according to your dialect, sometimes as e. A penny, tuppence, thruppence. However that does not mean nobody ever said "three pence" or "three pennies". Since three is plural, it was pence not penny, except when referring to the actual coin: a thruppenny bit.

Why was it pronounced that way? Through common and frequent usage. You say

English spelling and pronunciation do go hand in hand

but this simply isn't true.

In 1971 UK converted to decimal coinage, the 3d coin went out of circulation, and the way that we spoke of the coins changed overnight. People said the stilted "three new pence" and although we now had a 2p coin, where there was previously none, everybody stopped saying "tuppence"" and said "two new pence." It was many years before people again began to say "tuppence", but because there is no 3p coin, it is not very often that "three pence" needs to be said, and that accounts for your impression of it being an uncommon word: it is historical.

Aside: you might like to know of the adjective tuppenny-ha'penny (2½d) which means "almost worthless".

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    It's really interesting to know; however I don't see how it answers the question "why is threepenny pronounced /ˈθrɛpni/ and not */ˈθriːpɛni/".
    – Void
    Commented Nov 28, 2020 at 12:18
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    This conversation is making me feel very old! I remember the 'threepenny bit' well, and most people I knew did say 'threpni'. Why? I suppose different ways evolved of saying 'three penny' quickly, depending on your regional accent. Commented Nov 28, 2020 at 13:05
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    Always /θrʌpəni/ or /θrʌpni/ for me (and I do mean /i/ not /ɪ/ at the end).
    – Colin Fine
    Commented Nov 28, 2020 at 14:02
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    I'm a (UK) Southerner, and in most contexts my HUT and GUT are completely different to PUT and FOOT. But in my recollection, many Southerners referred to a thrOOpenny bit (short bOOk, not long bOOt) rather than a thrUpenny bit. Even though being Southerners, we naturally used tUpence rather than tOOpence. Commented Nov 28, 2020 at 15:11
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    I apologize for writing "do" instead of "don't". Please see the edit. I'm really sorry. And thanks for the answer.
    – user125597
    Commented Nov 30, 2020 at 10:05

threpni? All through my childhood in 1950s/60s England UK, it was pronounced thrupence / thrupnee, with the "u" pronounced as in "full". "Thrupence" was a very standard price for sweets (what US people call candy!) though there were plenty of sweets that could be purchased for less.

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    What part of this answers the question - why is it not pronounced like "three-penny"? Commented Nov 30, 2020 at 13:34
  • @TobySpeight Obviously your interpretation is good, but your version isn't actually what the question says: it does literally say (both in the title and in the body): why is it pronounced "threpni"? So "it's not" seems like a relevant answer, especially from a new user who doesn't have the reputation to make a comment instead. (In any case, do be nice to new contributors like it tells you in the comment box!) Commented Dec 1, 2020 at 16:03
  • @James, it is pronounced as in the title, in at least some places. Saying it's not isn't a helpful answer, and I've downvoted because of that. It's rude to downvote without a comment, so I did, perhaps in a hurry - thanks for the nudge re niceness! Commented Dec 1, 2020 at 17:47

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