As you have probably seen the very recent question Why are “south” and “southern” pronounced with different vowels?

The only (excellent) answer suggests that it is because of "Trisyllabic Laxing". (explained there in detail)

My question is: if the so-called trisyllabic laxing shortened the vowel in "southern", why doesn't it shorten the vowels in "northern" and "eastern"?

They also have the suffix "ern" and they would also be three syllables words in Old English (like "southern" was).

  • North = /nɔːθ/

  • East = /st/

  • Northern = /ˈnɔː.ðən/

  • Eastern = /ˈ.stən/

They have long vowels in their corresponding words "north" and "east" too. Is this irregular or there is an explanation for this?

  • Similarly with 'pronounce' and 'pronunciation' but the spelling is different too. Commented Nov 10, 2020 at 11:58
  • @WeatherVane: Pronounce - pronunciation is the result of Trisyllabic Laxing. About the spelling: It's because the digraph ⟨ou⟩ doesn't often represent the /ʌ/ vowel in Modern English, but ⟨u⟩ does. So the O has been removed for that reason. Also see profound - profundity.
    – Void
    Commented Nov 10, 2020 at 12:05
  • 1
    I spent more than two hours on tracing their roots and reading vowel shortenings/lengthenings but to no avail. :( I'll just add a comment and hope someone will come up with a good explanation. ///// 'North' is pronounced with a short vowel /ɔ/ in AmE (correct me if i'm wrong), but in BrE, it has a long version of the /ɔ/ vowel because of the deletion of r as BrE is non-rhotic (you lengthen the vowel after the deletion of r in other words too in BrE). 'North' had a short vowel in MidEng and Old Eng too. 'Northern' too had a short vowel in both MidEng and Old Eng, it's strange. [cont...]
    – Void
    Commented Nov 10, 2020 at 14:46
  • 1
    Both 'east' and 'eastern' had the vowel /æ͜ɑː/ in Old Eng. In Middle English, both had /ɛː/. And in ModEng, both have /iː/. /// 'Eastern' was trisyllabic in both MidEng and OE... I don't know what to make of it. I read several shortening and lengthening processes, but didn't come up with anything :(
    – Void
    Commented Nov 10, 2020 at 14:50
  • 1
    @rjpond: Good point! lore has a long vowel because r deletion,if the r had remained, it would've been a short vowel. Law has a long vowel too perhaps because it's an open syllable, and in open syllables, vowels were lengthened at some point. /// court has long vowel because of r deletion.... the long vowel in caught, night, knight etc is the result of compensatory lengthening triggered by the deletion of /x/ which was represented by the digraph gh. I suspect the long vowel in lawn is because of the vocalisation of the w. //// in lot, we have a short vowel because it's a closed syllable :)
    – Void
    Commented Dec 16, 2020 at 3:33

2 Answers 2


First of all, "trisyllabic laxing" is actually a controversial concept. The vowel alternations it is meant to explain clearly exist, but a number of phonologists think that it is not a correct description of either the origins of the vowel alternations in the relevant words, or the synchronic rule governing such vowel alternations (if the alternations are in fact governed by a rule).

Setting that aside, northern is easier to explain. The phonetically long vowel /ɔː/ here historically derives from a sequence of a short vowel + /r/ plus a consonant. This kind of long vowel regularly does not show trisyllabic laxing. There are many examples that show the absence of laxing/shortening, such as enormity, cortical, farcial, vertical, and various words ending in -ersity or -ernity.

The contrast between eastern and southern is not regular as far as I know. I don't know how it can adequately be explained.


The answer to this question is very complex if all details have to be included, but here's a short answer:

The only thing I notice about 'eastern' and 'northern' is that the first syllables of these words are closed syllables (have a consonant after the vowel in the same syllable); nor and eas and phonological processes like trisyllabic laxing and syncopation (loss of vowel) don't usually affect closed syllables. The first syllable of 'southern' is (and was) open syllable (/suː/), so it underwent Trisyllabic laxing.

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