Proto-Rathmosian/Later Developments

unstressed eC > iC and eyC > iyC
word-final, short a, e lost in words of 3 or more syllables: negara > negar
loss of word-final nasals -n, -m with nasalisation or preceding vowel, creating new ą, ę, į, ų, ɚ and ąą, ęę, įį, ųų
loss of word-final -t
raising of e > i, ew > iw and ey > iy before i or y in the next syllable
loss of y between vowels and contraction of remaining vowels
loss of word-final short, non-nasal vowels in words of 3 or more syllables: negani > negan
raising of a(a) > ä(ä), u(u) > ü(ü) before i, y in the following syllable
lowering of u(u) > new vowel o(o) before a(a), ä(ä), ą(ą) in the next syllable: kukad "he eats" > kokad.
unstressed diphthongs become long vowels: aw > oo, ay > ee, ew > oo, ey > ee
final-syllable long vowels shortened

Pr-Rs	Stressed	Unstressed	Word-Final	i-mutated	-n/-m
a	a	a / -	ä	ą
e	e	i	e / -	i	į
i	i	i / -		į
u	u	u / -	ü	ų
o (bef. a)
ə	ə			ę
aa	aa	a	ää	ą
ee	ee	e	ii	ę
ii	ii	i		į
uu	uu	u	üü	ų
oo	o
aw	aw	oo	o	äw	-ǫ
ew	ew	öö	e	iw	-ę
iw	iw	üü	i	iw	-į
uw	uw	uu	u	üw	-ų
ay	ay	ää	e	äy	-ę
ey	ey	ee	e	iy	-ę
iy	iy	ii	i		-į
uy	uy	üü	i	uy	-ų

The changes described above resulted in the following vowel inventory for the late common period:

ə(ə) > e(e), ɚ > a
nasals followed by fricatives are lost, leading to compensatory lengthening and nasalisation of preceding vowel: negans > negąąs
Cy > CC, except ry
g > /ɣ/ in most positions, except ng, gg
p, t, k > f, þ, h and b, d > v, ð before n, m, l, r
a(a) and ay raised to ä(ä), äy except before -n, -m or before a back vowel (a(a), o(o), u(u)) in the next syllable
- unstressed äC > eC
word-final -a lost
nasal vowels merge with non-nasal counterparts
stressed ä, e, i > äw, ew, iw before -w, -lC, rC
changes to diphthongs: ay > ae, aw > ao, äy > äe, äw > äo, ey > ee, ew > eo, uy
k, g, sk palatalised to ch /t͡ʃ/, ȝ /ʝ/, sh /ʃ/ (a) before a front vowel (ä, e, i, ü) or y, or (b) after e, i except when followed by a back vowel: negara > neger > neȝer but neganta > negan
i-mutation: a(a) > ä(ä), e(e) > i(i), o(o) > ö(ö), u(u) > ü(ü) before i, y in next syllable
word-final -i, -u lost, except after light monosyllable
unstressed vowel reduction:
- medial syllable: a, ä, e lost, i, u lost after heavy syllable, > e after light syllable, oo > o, other long vowels > short
- final syllable: ä, i > e, uC > oC, oo > u, other long vowels > short

ə(ə), ɚ > a
nasal vowels merge with non-nasal counterparts
i-mutation: a(a) > ä(ä), o(o) > ö(ö), u(u) > ü(ü) before i, y in next syllable
stressed e(e) > ja(a), except after l, w
u-mutation: a(a) > o(o), ja(a) > jo(o), ä(ä) > œ(œ), e(e) > ö(ö), i(i) > ü(ü)
y lost before front vowels and w before back vowels, except a
devoicing of word-final consonants
mp, nk, nt > pp, kk, tt