pronunciation rule for grapheme "a" in words like "nefarious," "variation" and "temporary"

Question

English pronunciation / spelling guides appear to state that the letter/grapheme "a" is pronounced either as the "short a" with IPA symbol /æ/, as in "mat" or the "long a" with IPA symbol /eɪ/, as in "baby."

However, apparently there exist multiple words where all references I checked provide the spelling of "short e" with IPA symbol /e/ or /ɛ/ which I take as a variation in the IPA transcription not in the underlying pronunciation.

What I'm unable to come up with or find a reference for is when will the grapheme "a" be pronounced as /e/ (or /ɛ/) instead of the short "a" /æ/ that the typical rules would predict?

Examples of words that have "a" transcribed as /e/: - temporary - nefarious - compare - share - dare - subsidiary (many more have two alternative pronunciations listed, one with /æ/ and one with /e/)

I recognize that all these examples include the sequence "ar" but I do not know if this is only because I was searching for this sequence in a corpus (based on the original example of "nefarious") or because there exist no other cases.

Actually, I find that my most trusted reference "The ABC's and all their tricks" by Margaret M. Bishop is including some of these words in the group of "-arr-" as in "carry", which my dictionaries transcribe as /ˈkæri/. This mixes two different pronunciations under the same rule. Is there no "rule" to help predicting the /æ/ or /e/ realization?

Answer 1

Except for words imported from non-Latin/Germanic languages, words with ortography matching the following regular expression will have the matching part realized as /er/: *a[ei]r[iey]* provided that the matching syllable has the word-stress.

In the "Shorter Oxford English Dictionary" (BrE pronunciations) the expression matches over 450 headwords (including false positives where "a" is not in a stressed syllable) with only a couple exceptions, like "Bohairic" (via Arabian), "dairi" (via Japanese), "etaerio" (From Greek via French; exception to the non-Latin precondition). In the cases that I investigated Merriam-Webster's Collegiate was also providing the phoneme /e/ for the syllable that includes the letter "a".

It appears that if the consonant was not "r" then the realization would be most often /ei/ (as in "tale", "calix", "agave" (BrE), "baby","navy", "zamia") but the "r" reduces that to the less heavy /e/. The rise is likely related to the stressed syllable being open.

There exist other examples, with all requiring that the 'a' be in a stressed syllable but there appear to be more exceptions than matches in the cases that I investigated ("scarus", "marum", "larum", "garum", --> /e/ but most other matches are a false positive).

This observation mostly matches the first comment of Janus Bahs Jacquet but strengthens the conditions for the raise to happen. Will be glad to revise if someone is able to provide a condition that provides a higher accuracy.

Answer 2

All your examples have latin roots. Wary is a germanic root word with a similar pronunciation. Scary is from Old Norse. Wary is rather interesting - the a is pronounced the same in wary and in beware. But in ward and warn it changes to rhyme with sword and sworn. It almost feels like this has 'stolen' that sound for w, so word and worry match with turd and third.

Answer 3

As Peter Shor said,

You seem to be using both British and American dictionaries. These two dialects have completely different rules for pronunciation of vowels before 'r' (and note that it varies between different American dialects, and between different British dialects).

What this comes down to is that some dialects have no distinction between a "short a" sound, a "long a" sound, or a "short e" sound before /r/. Other dialects do. You can see more description here: How are 'marry', 'merry', and 'Mary' pronounced differently?

Basically, dialects with a three-way distinction have something like /ær/, /eə̯r/ and /ɛr/ respectively in marry, Mary and merry.

In dialects with a merger of these three sounds, the merged sound is generally written as /er/ or /ɛr/.

The grapheme "ar", when before a vowel, can generally represent either /ær/ or /eə̯r/ in non-merged dialects.

The rules that apply (in dialects that maintain the distinction) are the same as apply for determining whether to use a "long a" /eɪ/ or "short a" /æ/ before other consonants besides "r". For example, in words like "nefarious" or "variation" where "ar" is followed by "i" and then another vowel, the "ar" is almost always long /eə̯r/, just as in the words "gracious" or "aviation" the "a" is "long" /eɪ/. In words like "share" or "compare" that end in a silent e, the "ar" is almost always long /eə̯r/, just as in words such as "rate" the "a" is long /eɪ/.

An example of where "ar" would usually be short /ær/ is in a third-to-last syllable before a single vowel letter. Examples: marinate /ˈmærɪˌneɪt/, clarity /ˈklærɪti/, charity /ˈtʃærɪti/. The word rarity /ˈrɛərɪti/ is an exception to this general principle; ar in this word has been lengthened by analogy with the adjective rare, like how the e in obesity has been lengthened by analogy with the adjective obese.

Words ending in "-ary", like temporary and subsidiary, are unusual. Because the vowel is unstressed, it is usually reduced or even outright dropped in British English, giving /(ə)ri/. In American English accents that don't have the merger, it is not common to reduce the vowel to schwa, but it is generally shortened to /ɛr/. The suffix "-ary" is one of the only places where "ar" corresponds to /ɛr/ in non-merged accents.

Obviously, in accents with the merger, you can just use /eə̯r/ or /ɛr/ indifferently.