S. later [ei] became [ai] in final syllable; [ei] > [ai]

final syllable only? teitha- @@@

Phonetic Rule Elements

[ei] > [ai]

Phonetic Rule Examples

eir > air ei > ai eryā > eir > S. air ✧ PE17/028.1806
beleiθ > belaiθ ei > ai mbelek > S. belaith ✧ PE17/115.1606
feir > fair ei > ai pheryā > feir > S. fair ✧ PE17/181.0605
geil > gail ei > ai gilyā > geil > S. gail ✧ PE17/152.0105
gweiθ > gwaiθ ei > ai weg-tē > S. gwaith ✧ PE17/190.0201
keil > kail ei > ai keglē > S. cail ✧ UT/282.0405
leix > laix ei > ai lisyā > liχı̯ā > leχı̯ > leich > S. laich ✧ PE17/148.3310
mein > main ei > ai minya > mein > S. main ✧ VT42/25.1806
neiθ > naiθ ei > ai nek-tē > neith > S. naith ✧ PE17/055.0302
reiθa- > raiθa- ei > ai RIK > S. raitha ✧ PE17/167.1609
teiθ > taiθ ei > ai tek-tā > teith > S. taith ✧ PE17/043.2714

N. later [ai] coallesced with [ei]; [ai] > [ei]

GS/§4.199 GS/§4.232 @@@ Feanorian maið

Order (02700)

After 01100 [ɣ], [ŋ] vocalized before [l], [r], [m], [n] ᴹ√REG > rhein > N. rhain Ety/REG
After 02300 final [j] intruded into preceding syllable ᴹ✶bányā > N. bein
ᴹ✶kalaryā > N. celeir
Ety/BAN
Ety/KAL
After 02400 initial [r], [l] were unvoiced ᴹ✶(a)ranı̯ā > rhain > N. rhein
ᴹ√LEK > lhein > N. lhain
EtyAC/RAN
Ety/LEK
After 02600 voiceless stops voiced after vowels ᴹ✶mrekjā > breig > N. braig Ety/MERÉK

Phonetic Rule Elements

[ai] > [ei]
[ei] > [ai]

Phonetic Rule Examples

bain > bein ai > ei ᴹ✶bányā > N. bein ✧ Ety/BAN.038
fain > fein ai > ei ᴹ√SPAN > N. fein ✧ Ety/SPAN.008
faira- > feira- ai > ei ᴹ√PHAR > N. feira- ✧ EtyAC/PHAR.064
kelair > keleir ai > ei ᴹ✶kalaryā > N. celeir ✧ Ety/KAL.053
maið > meið ai > ei ᴹ√MAD > N. meið/maið ✧ Ety/MAD.008
r̥ain > r̥ein ai > ei ᴹ✶(a)ranı̯ā > rhain > N. rhein ✧ EtyAC/RAN.014
xair > xeir ai > ei ᴹ√KHYAR > N. heir ✧ Ety/KHYAR.015
eiθ > aiθ ei > ai ᴹ√EK > N. aith ✧ Ety/EK.010
breig > braig ei > ai ᴹ✶mrekjā > breig > N. braig ✧ Ety/MERÉK.037
l̥ein > l̥ain ei > ai ᴹ√LEK > lhein > N. lhain ✧ Ety/LEK.008
r̥ein > r̥ain ei > ai ᴹ√REG > rhein > N. rhain ✧ Ety/REG.008

ᴱN. [ei] became [ai]; [ei] > [ai]

Phonetic Rule Elements

[ei] > [ai] ✧ PE15/64.0602 (eı̯ > ai); PE15/64.1402 (eı̯ > ai)