Have "pay" and "paid" the same vowel?

[CJ 4 life]

Hi, I've been told that the first part of the diphthong "pay" has an open "E" (pEy) and so are all the words that have this diphthong in final position (sEy, lEy, mEy,...) whereas "paid" has a closed "e" (peyd) and so are all the words that have this diphthong in the middle of the word (sheyk, keym, meyd,...) I that true? Is there a rule for this?

[BobK]

"Pay" and "paid" have the same vowel (/eɪ/), but "say" and "said" don't (/eɪ/ and /e/). The accepted pronunciation today is set on the basis of whichever regional pronunciation happened to be the most influential when the word entered the language - with sometimes illogical results. You just have to learn them, I'm afraid.

b
PS ...but the most common form is regular:
bay/bayed
lay/laid
may/maid/made
nay/neighed (what a donkey did!)
pay/paid
way/weighed/wade - ALL /eɪ/. It's only say/said that's irregular in this case.

(There are other more obscure words, but they're of no interest to ELT students)

[Anglika]

Originally Posted by BobK

nay/neighed (what a donkeyhorse did!) bray/brayed is what donkeys do

[BobK]

I initially thought of "bray/braid" ( which as Anglika knows is an acceptable word, and is pronounced with the same vowel) - but it's just not a simple past; but if I'd admitted nouns into the pattern I'd have had to deal with another irregularity ("plaid") , which isn't pronounced with that vowel:

braid definition |Dictionary.com
plaid definition |Dictionary.com

b

PS there's also http://dictionary.reference.com/browse/staid, but "stay/staid" was only an infinitive/past pair many years ago; today, the simple past of "stay" is "stayed", and "staid" is an adjective that means something else entirely.