The standard Lexical sets for English were introduced by professor John Wells which are widespread. Each lexical set represents a vowel present in a number of words, for example: the THOUGHT vowel /ɔː/ is found in taught, sauce, hawk, jaw, broad. The GOAT vowel /əʊ/ is found in soap, joke, home, know, so, roll etc.

However, there are three lexical sets NORTH, FORCE and THOUGHT for the same vowel /ɔː/ especially in British English. He has included different words in each lexical set:

  • THOUGHT: taught, sauce, hawk, jaw, broad
  • NORTH: for, war, short, scorch, born, warm
  • FORCE: four, wore, sport, porch, borne, story

(All the above information comes from Wikipedia)

All those words sound the same to me (a non-native speaker of English who is learning British English). I can't detect any difference between them and looking the sets up on UCL website, there is no information on whether there is any difference between them or not.

Why did John Wells need three lexical sets for the same vowel when he could easily have incorporated those words in one lexical set (say for example THOUGHT)? Are those vowels--NORTH, FORCE and THOUGHT--different in British English? Can anyone provide the phonetic values/realizations of those vowels they have in British English?


I emailed professor John Wells and asked him why there were three Lexical sets for the same vowel. I said to him "someone (I meant @Nardog) told me that the whole point of lexical sets is to make it easier to describe differences between [vowels in different] accents. He replied to me and said:

"Someone" is correct. And not only American English, but also Scottish English and various other varieties. Read the book!

John Wells

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    Prof. John C Wells has a public page that gives his email address. Rather than get a second guess, why not ask him directly? phon.ucl.ac.uk/home/wells
    – Greybeard
    Commented Apr 25, 2021 at 10:08
  • Have you tried looking them up in a dictionary with British English pronunciations (e.g. Oxford or Cambridge)?
    – Stuart F
    Commented Apr 25, 2021 at 10:30
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    The clue is in the word set, they are a set of exemplars of the THOUGHT vowel from BrE. They have no difference in quality of any note. Commented Apr 25, 2021 at 11:49
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    Native BrE speaker: IMO "for", four," and "fought" are the same vowel sound but with subtly different lengths of the sound. (I assume "fought" would be in the same set as "thought").
    – alephzero
    Commented Apr 25, 2021 at 17:41
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    @Commenters: Just because a group of words belong to the same lexical set doesn't mean they're pronounced completely the same. It just means that they are identified with the same phoneme within RP or GenAm.
    – Nardog
    Commented Apr 25, 2021 at 19:54

2 Answers 2


Because they differ in (Wells's model of) General American.

The whole point of lexical sets is to make it easier to describe differences between accents. Since not only phonetic values but the distribution of phonemes vary across accents, it's often not enough to say e.g. "What is phoneme X in Received Pronunciation is realized as Y in this accent" when describing an accent. By using lexical sets, you can illustrate the features of an accent in a succinct way.

In Wells's model of GenAm, THOUGHT/NORTH/FORCE have /ɔ/, /ɔr/, and /or/ (GOAT + /r/), respectively. Note that Accents of English was published in 1982 (and written mostly in the 1970s). Obviously nowadays in the US, NORTH and FORCE are mostly merged, and THOUGHT is increasingly being merged with PALM.

Wells's are called "standard" lexical sets because they derive from the differences between RP and GenAm. This means some accents differ in ways that the standard sets cannot account for. For instance, some varieties of Scottish English use different vowels in fern, fir, and fur, which all belong to the NURSE set.

  • That is what I was going to suggest roughly. There seems to be no other reason.
    – LPH
    Commented Apr 25, 2021 at 11:45
  • Even when Wells came up with the lexical sets, Most Americans pronounced NORTH and FORCE the same way. I think he made the distinction because they were still distinct in several dialects. But the distinction is steadily disappearing. In Boston, one of the last holdouts of the distinction between NORTH and FORCE, NORTH is indeed /ɔ/ (no /r/) but FORCE is /oə/. Another holdout is some regions of the South, but they pronounce all their vowels differently, so I expect they don't use /ɔr/ and /or/, either. Commented Apr 25, 2021 at 17:47
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    I grew up in the 60s, speaking a fairly standard American dialect, and I never pronounced NORTH and FORCE differently. But enough Americans did that the American Heritage Dictionary distinguished between these lexical sets in their pronunciations until the 5th edition (2011). Commented Apr 25, 2021 at 18:04
  • GOAT+/r/? So e.g. "story" would have the same /or/ sequence as in "showroom"? Sounds unlikely.
    – Rosie F
    Commented Apr 25, 2021 at 18:09
  • @RosieF It's a phonemic notation. Since GOAT + /r/ is otherwise not found in monomorphemic words, GOAT is pretty much the only option to attribute a close-mid rounded vowel that precedes /r/ to. What's more, in accents that merge both NORTH/FORCE and LOT/THOUGHT (as in many parts of the US and most of Canada), /or/ is the only possible analysis for NORTH/FORCE (unless you're heretical enough to posit separate phonemes for R-colored vowels).
    – Nardog
    Commented Apr 25, 2021 at 19:44

A lexical set does not represent a vowel.

It represents a set of words that are all pronounced with the same vowel phoneme in Wells's two reference accents of "Received Pronunciation" and "General American". These are artificial standards and as Nardog says, Accents of English was written several decades ago, so this is not exactly equivalent to "British English" and "American English".

This means any word in the NORTH set is pronounced with the same vowel phoneme as any other word in the NORTH set, any word in the KIT set is pronounced with the same vowel phoneme as any other word in the KIT set, and so on.

It does not mean that words in different lexical sets always have different vowel phonemes: that is not the case. Neither accent uses a separate distinct vowel for each of Wells's lexical sets. But the sets that have identical vowels differ between the two accents.

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