Proto-West Persian'

The branch further divides into the Bustaxoid and Tsonboid languages.

Changes from Proto-Persian'

• high vowels
  • ɪ ʊ ɪː ʊː → i u əj əw
  • ɪw ɪj ʊj → iw iː uj
• loss of difthongs in _w
  • ⁽ʰ⁾k → ⁽ʰ⁾kʷ / w_
  • iw → yː
  • ew → e₂ː
  • æw → æː
  • ow → uː
  • əw → o₁ː
• more labiovelars
  • kw → kʷ
  • k⁽ʰ⁾uj → k⁽ʰ⁾ʷiː
  • k⁽ʰ⁾o₁ː → k⁽ʰ⁾ʷe₁ː
  • k⁽ʰ⁾ɒː → k⁽ʰ⁾ʷaː / before a coronal consonant
• /i u/ lost initially before a single consonant; any newly initial velars occurring after /u/ labialized
• phonation/MOA changes
  • intervocalic lenition: b d → β ð
  • intervocalic voicing: p t s ɬ k⁽ʷ⁾ q χ → b d z ɮ ɡ⁽ʷ⁾ ɢ ʁ
  • loss of aspiration
    • ʰp ʰt ʰk⁽ʷ⁾ ʰq → p t k⁽ʷ⁾ q
    • pʰ tʰ kʰ⁽ʷ⁾ qʰ → ɸ θ x⁽ʷ⁾ χ
    • hh → χ
  • stop clusters with a 2nd voiced member become voiced thruout
• lo vowels
  • æ ɐ æː ɒː → a ə aː o₂ː
• development of an initial mutation system from prefixation + partial or total elision of various function words
  • t-mutation: P → B, b d r w j → tw tr tr tw tj, aspirates (??), other consonants unaffected
  • q-mutation: (from Vq)
  • p-mutation: (from pV)
  • w-mutation: (from Vw or perhaps u) k x → gʷ xʷ, b d → β ð, P → B, other consonants unaffected (some relict cases of χ₂ → ʁ exist)
  • null mutation: (from Vh) B → P, F → P (but s, ɬ, χ₂ unaffected), h → χ, r w j → χr xʷ x, other consonants unaffected
  • m-mutation: initial /m/ occurs as syllabic; |mb mw| → /mm/, |mn md| → /nn/, |mr ml| (regularly) → /ms mɬ/

Intermediate form

Consonants

p	t			k	kʷ	q
b	d			ɡ	ɡʷ	ɢ
ɸ	θ	s	ɬ	x	xʷ	χ	h
[β	ð	z	ɮ]			ʁ
m	n	r	l	j	w

No evidence pointing to labialized uvulars exists.

[β ð z ɮ] are best analyzable as intervocalic allophones of their unvoiced counterparts. /χ/ and /ʁ/ do contrast, tho intervocalic /χ/ occurs only in inflection and is usually somewhat longer [χˑ].

Carrying over from Proto-Persian' was the feature that both nasals could occur before just about any consonants, apparently without any POA assimilation taking place. The existence of a separate, prenasal onglide for the folloing consonant has been proposed.

Cluster/sandhi table

Color key
Plain consonant clusters; may occur morpheme-internally
Plain consonant clusters with regular subphonemic modifications
Contrast neutralization
Intermorphemic only
Intermorphemic sandhi
Interword (?) sandhi
Epenthetic /u/

K, G, X are cover symbols for dorsals /k kʷ q/, /ɡ ɡʷ ɢ/, /x xʷ χ/.

Coda → Onset ↓	p	t	K	h	m	n	∅
ɸ	N/A	tɸ	Kɸ	p	mɸ	nɸ	β
p	N/A	tp	Kp		mp	np	b
b	N/A	db	Gb		m		β
θ	pθ	qθ	Kθ	t	mθ	nθ	ð
t	pt	qt	Kt		mt	nt	d
d	bd	tr	Gd		n		ð
X	pX	tX	tX	K	mX	nX	-
K	pK	tK	tK		mK	nK	G
χ2	uʁ	χ			(mχ)	(nχ)	(ʁ)	Exception class from original *χ.
s	N/A	qs	Ks	hs	ms	ns	z
ɬ	N/A	ql	Kl	hɬ	mɬ	nɬ	ɮ
ʁ	N/A	tʀ	qʀ	hʀ	mʁ	nʁ	ʁ
h	p	t	K	χ	mh	nh	h
m	N/A	m		hm	m		m
n	N/A	n		hn	n		n
r	pr	tr	Kr	hr	ms	ns	r
l	pl	ql	Kl	hl	mɬ	nɬ	l
j	pj	tj	K(ʀ)j	hj	mj	nj	j
w	N/A	tw	K(w)	hw	m	nw	w

Vowels

The short vowel inventory is /a e ə o i u/, the long vowel inventory /aː eː oː iː yː uː/. Difthongs are /aj ej əj uj/.

Two distinct types of /eː oː/ are reconstructed for PWP'. Most likely these are /eː oː/ and /ɛː ɔː/, but it remains unclear which are which. An alternate theory proposes a roundedness distinction insted with /øː ɤː/, but with little additional clarification.