Is there a known reason for the position of the stress in "concupisc-" words in English?

Question

The words concúpiscent, concúpiscence, concúpiscible seem to be irregularly stressed (at least, according to their dictionary pronunciations; regularized pronunciations apparently have been heard "in the wild") when compared to words like reminíscent(-ce), dehíscent(-ce), oblivíscible, immíscible, permíscible, not to mention a lot of other words with -éscent(-ce).

I found this exception mentioned in the fourth edition of John Walker's "Critical Pronouncing Dictionary" (1846), but there is no explanation given. The Oxford English Dictionary entries for these three words also don't explain the pronunciation.

Has anyone attempted to do so?

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I tried to think of possible reasons, and the only thing I could come up with is possible stress shift from an original Middle English concupiscént/concupiscénce (taken from the stress in French or in Latin concupiscentia) via the somewhat common pattern of putting secondary stress on alternating syllables. Whereas, presumably, the other -scent/-scence words either came into English at a later period, when word-final stress was no longer common, or their pronunciation was remodeled for some reason while that of concupiscence etc. was not.

The OED's earliest citation is "c1340," spelled "concupyscens" which does seem earlier than the first OED citation for "adolescence" ("?a1425") or "pubescence" (?a1425). I also wasn't able to find any earlier attested use of an "-escence" word in the Middle English Dictionary quotations.

Even if nobody knows about these specific words, I would appreciate any more general information on the stress patterns of words ending in -ence or -ance in Middle English, and how they may have changed in the development to present-day English.

Answer 1

If I understand Walker, he's saying the regular case is words like "quiESCence", with accent on the penult. If "concupiscence" were stressed on the penult, it would be pronounced "concuPISSence", which sounds vaguely obscene.

Answer 2

This is more of a bit of musing than a proper answer, but it could be the reason that at least the first two have this seemingly irregular stress pattern.

Concúpiscent and concúpiscence don't sound oddly stressed to me at all—in fact they sound perfectly acceptable and normal, despite the fact that I'm quite sure I've never heard anyone say either word. Concúpiscible, on the other hand, sounds downright bizarre.

Like you, I could find no other parallel for an -Vscence/-Vscibility word having the stress on the syllable before the -sc-, so it puzzled me that I find concúpiscent/-ce so normal-sounding.

I tried to figure out what pattern made -úpiscent sound perfectly normal—and it finally hit me: magnificent and its ilk!

The -ficent suffix is etymologically unrelated, of course (apart from stemming from Latin participles), but it is phonetically /ˡVCɪsənt/ with antepaenultimate stress, just like what we find in concupiscent. And unlike more closely related word like reminiscent and dehiscent, there's no base verb *concupisce to show where the stress should go.

So I would theorise that perhaps concupiscent/-ce, wherever the stress originally lay, may have retracted its stress due to phonetic similarity with words in -ficent.

That doesn't account for concupiscible, of course, and I'll admit that I'm stumped there. Looking through a reverse dictionary I cannot find a single other word ending in -cible that has preantepaenultimate stress—it seems to be totally irregular and counter to all logic.