Why are "suffice" and "sufficient" pronounced so differently?
Today I heard somebody use a form of the verb "suffice" (which means "to be sufficient") pronouncing it like the verb "surface" without an r (and where that "a" makes more of an "i" sound). This person was logically, but incorrectly, adopting the "i" sound from "sufficient" which shares a root and meaning. The consonant sound in that second syllable is also quite different between the two words (having the c more like a z than an sh).
Why is this?
Other similarly puzzling questions:
- Why A is pronounced differently in "opacity" and "opaque"
- Why are the first syllables of “nature” and “natural” pronounced differently?
- Why are "nation" and "national" pronounced differently?
- Why are "look" and "school" pronounced differently?
- Why are Kansas and Arkansas pronounced differently?
I suspect Trisyllabic laxing might answer part of the question, but I don't think that explains it all.
Solution 1:
It's not trisyllabic laxing in the strict sense, since the stressed vowel is in the second-to-last syllable rather than the third-to-last in normal pronunciation. However, some researchers seem to consider all laxing processes in English to be related at an underlying level. I've just read a paper, "English Syllable Structure and Vowel Shortening" by Balogné Bérces Katalin, which talks about -ion shortening (seen in words like divide, division); it mentions that this only laxes the vowel i (for example, invade, invasion does not show laxing). This seems to be the relevant process here, although the suffix is not -ion but -ient. In a parallel fashion, the only vowel affected is i; words like quotient and patient have tense vowels. (This is one way this process differs from normal trisyllabic laxing, which applies to all of "a," "e," "i" and "o" as in insane/insanity, serene/serenity, divine/divinity and verbose/verbosity.) I'm still working on processing the paper and understanding the reason why this process applies, but Balogné Bérces connects it to the y-sound in the suffix. This palatal sound is also clearly the cause of the /ʃ/ ("sh") sound in sufficient, compared to the /s/ ("ss") sound in suffice. Neither of them is normally pronounced with /z/, so I'm not sure why it sounds like that to you.
I believe the difference between "office" and "suffice" is because the former is a noun and the latter is a verb; disyllabic nouns in English tend to be stressed on the first syllable, and disyllabic verbs to be stressed on the last.