Editing Openai/69186d20-2d14-8013-b9c6-c09000f173f6 (section)

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Spelling: c a i f e
Pron: /ˈkafʲə/
# Stress on cai-.
# Vowels in first syllable: a, i. No absolutely obligatory digraph like ae / ao here.
# We want: - broad c (underlyingly; matches lots of forms like cáife etc.) - slender f (because of final e and general pattern of café-type loans)

A consistent parse:
* a = the real vowel /a/ of the stressed syllable.
* i = no independent vowel in the target pronunciation → treat it as mainly a slenderizer for f, but historically also part of a digraphish spelling; in modern standard /ˈkafʲə/ it contributes no separate vowel.
* e (final) = /ə/ and also keeps f slender.

So here the role of i is basically “extra slender support” for f; caife is a loan and a bit messier than native patterns, but this reading is consistent with the system.

===== b a i n n e → /ˈbˠanʲə/ =====
* Syllabify: bainne ≈ bain-ne.
* ai in the first syllable: - Vowel we actually hear: /a/. - a is the syllable vowel; i’s main role is to make n slender.
* Final e = /ə/, and again a slenderizer for preceding n.

So:
* a = real vowel, broad for b.
* i = mostly slender marker (no separate /i/).
* e = real /ə/ + slender marker.

This is a very clean example of “sound vs class marker”.

===== m a i t h → /mˠah/ =====
* First syllable stressed; cluster maith is one syllable.
* ai: vowel heard is /a/.
* a is real vowel; i exists to keep the underlying t slender (even though it surfaces as lenited th [h]).

So ai = [a] + slender flag for the consonant to its right.

===== t a e → /t̪ˠeː/ =====
* Here ae really is a standard digraph → /eː/.
* There’s no extra vowel that “just” marks slenderness; the consonant t is broad anyway.

So ae is firmly type (3): digraph → one monophthong.

===== s i ú c r a → /ˈʃuːkɾˠə/ =====
* ú = long vowel /uː/, easy.
'' i before s: - No extra vowel in the actual sound; we get /ʃuː…/, not ''/siuː…/. - So i’s main function is to make s → ʃ, i.e. slenderize it with no independent vowel.

That’s your prototype of a pure class marker vowel.