Indo-European sound laws

As the Proto-Indo-European language (PIE) broke up, its sound system diverged as well, as evidenced in various sound laws associated with the daughter Indo-European languages.

Especially notable is the palatalization that produced the satem languages, along with the associated ruki sound law. Other notable changes include:

• Grimm's law and Verner's law in Proto-Germanic
• an independent change similar to Grimm's law in Armenian
• loss of prevocalic *p- in Proto-Celtic
• Brugmann's law in Proto-Indo-Iranian
• Winter's law and Hirt's law in Balto-Slavic
• merging of voiced and breathy-voiced stops, and /a/ and /o/, in various "northern" languages

Bartholomae's law in Indo-Iranian, and Sievers's law in Proto-Germanic and (to some extent) various other branches, may or may not have been common Indo-European features. A number of innovations, both phonological and morphological, represent areal features common to the Italic and Celtic languages; among them the development of labiovelars to labial consonants in some Italic and Celtic branches, producing "p-Celtic" and "q-Celtic" languages (likewise "p-Italic" and "q-Italic", although these terms are less used). Another grouping with many shared areal innovations comprises Greek, Indo-Iranian, and Armenian; among its common phonological innovations are Grassmann's law in Greek and Indo-Iranian, and weakening of pre-vocalic /s/ to /h/ in Greek, Iranian and Armenian.

Consonants

The following table shows the Proto-Indo-European consonants and their reflexes in selected Indo-European daughter languages. Background and further details can be found in various related articles, including Proto-Indo-European phonology, Centum and satem languages, the articles on the various sound laws referred to in the introduction, and the articles on the various IE proto-languages, language groups and language phonologies. For development of the laryngeals and syllabic consonants, see the vowels table below.

Table 1. Reflexes of Proto-Indo-European single consonants

PIE	Indo-Iranian		Balto-Slavic		Alb.	Arm.	Anatol.	Toch.	Greek		Italic	Celtic		Germanic
	Skr.	Av.	O.C.S.	Lith.			Hitt.				Latin	Old Irish		Gothic	English
									normal	C+[j]		normal	-C-^8
*p	p; ph [pʰ] [C 1]	p; f^17	p			h; w [C 2]	p, pp	p		pt	p	Ø		f; b [β] [C 3]	f; v, f^8
*t	t; th [t̪ʰ] [C 1]	t; θ^17	t			tʿ [tʰ]	t, tt; z [ts] [C 4]	t; c [c] [C 4]	t	s; tt/ss[C 2]	t	t	th [θ]	þ [θ]; d [ð]; [C 3]	th; d; [C 3]
*ḱ	ś [ɕ]	s		š [ʃ]	th [θ]; k^9	s	k, kk	k; ś [ɕ]^9	k		c [k]	c [k]	ch [x]	h; g [ɣ] [C 3]	h; Ø;^8 y [C 3]
*k	k; c [t͡ɕ]; [C 4] kh [kʰ] [C 1]	k; c [tʃ]; [C 4] x^17	k; č [tʃ]; [C 4] c [ts]^10	k	k	kʿ [kʰ]
*kʷ					k; s; [C 4] q [c]^10		ku, kku		p; t; [C 4] k^6		qu [kʷ]; c [k] [C 5]			ƕ [ʍ]; gw, w [C 3]	wh; w [C 3]
*b	b; bh [C 1]	b; β [C 6]	b			p			b	pt	b	b [b]	-[β]-	p
*d	d; dh [C 1]	d; δ [C 6]	d		d; dh [ð]^8	t		ts; ś [ɕ] [C 4]	d	z [zd] > [z]	d	d [d]	-[ð]-	t
*ǵ	j [d͡ʑ]; h [ɦ] [C 1]	z		ž [ʒ]	dh [ð]; g^9	c [ts]	k	k; ś [ɕ]^9	g		g	g [ɡ]	-[ɣ]-	k	c / k; ch^10
*g	g; j [d͡ʑ]; [C 4] gh; [C 1] h [ɦ] [C 1] ^5	g; j [dʒ]; [C 4] γ [C 6]	g; ž [ʒ]; [C 4] dz^10	g	g	k
*gʷ					g; z; [C 4] gj [ɟ]^10		ku		b; d; [C 4] g^6		u [w > v]; gu [ɡʷ] [C 7]	b [b]	-[β]-	q [kʷ]	qu
*bʰ	bh [bʱ]	b; β [C 6]	b			b; w^8	p		ph [pʰ]	pt	f;^21 b			b [b]; b [β];^8 f [C 8]	b; v / f^24
*dʰ	dh [dʱ]	d; δ [C 6]	d				t	t; c [c] [C 4]	th [tʰ]	tt/ss	f;^21 d; b [C 9]	d [d]	-[ð]-	d; d [ð];^8 þ [C 8]	d
*ǵʰ	h [ɦ]	z		ž [ʒ]	dh [ð]; d^9	j [dz]; z^8	k	k; ś [ɕ] [C 4]	kh [kʰ]		h; h / g^9	g [ɡ]	-[ɣ]-	g; g [ɣ];^8 g [x] [C 8]	g; y / w^24
*gʰ	gh [ɡʱ]; h [ɦ] [C 4]	g; j [dʒ]; [C 4] γ [C 6]	g; ž [ʒ]; [C 4] dz^10	g	g	g; ǰ [dʒ] [C 4]
*gʷʰ					g; z; [C 4] gj [ɟ]^10		ku		ph [pʰ]; th [tʰ]; [C 4] kh [kʰ]^6		f;^21 g / u [w];^8 gu [ɡʷ] [C 7]			g; b;^21 w;^8 gw [C 7]	g; b;^21 w^8
*s	s	h [h, x]	s		sh [ʃ]; gj [ɟ];^12 h^8	h; Ø^8	š [s]	s; ṣ [ʂ]	h;^21 s;^22, 13 Ø;^8 [¯] [C 10]	i	s; r^8	s ʃ	-[h]-	s; z [C 3]	s; r [C 3]
	ṣ [ʂ]^11	š [ʃ]^11	x [x]^11	š [ʃ]^11
*m	m									in	m	m [m]	-[w̃]-	m
*-m [C 8]	m		˛ [˜]	n		Ø	n	n		--	m [˜]	n		Ø
*n	n		n; ˛ [˜] [C 8]	n				n; ñ [ɲ]	n	in	n
*l	r (dial. l)	r	l		l; ll [ɫ]^8	l / ɫ [ɫ > ɣ]	l			il	l
*r	r				r [ɾ]; rr [r]^8	r				ir	r
*y	y [j]		j [j]		gj [ɟ]; Ø	Ø	y [j]		z [zd] > [z] / h; Ø ^8	?i	i [j]; Ø ^8	Ø		j	y
*w	v [ʋ]	v [w]	v	v [ʋ]	v	g / w	w		w > h / Ø	i	u [w > v]	f	-Ø-	w
PIE	Skr.	Av.	O.C.S.	Lith.	Alb.	Arm.	Hitt.	Toch.	Greek	Greek+/j/	Latin	Old Irish		Gothic	English

Notes for table 1:

1. Before an original h₂.
2. After a vowel.
3. Following an unstressed vowel (Verner's law).
4. Before a (PIE) front vowel (*i, *e).
5. Before or after a (PIE) rounded vowel (*u, *o).
6. In Younger Avestan, after a vowel.
7. After n.
8. At the end of a word.
9. After u, r or before r, l.
10. Before or after a resonant (r, l, m, n).

Notes for table 1 and table 2:

⁶ Before or after a (PIE) u.

⁸ Between vowels.

⁹ Before a sonorant.

¹⁰ Before secondary (post-PIE) front-vowels.

¹¹ After r, u, k, i (Ruki sound law).

¹² Before a stressed vowel.

¹⁷ Before a consonant or original laryngeal.

¹⁹ After r, l, m, n, t, d, possibly other consonants?

²¹ At the beginning of a word.

²² Before or after an obstruent (p, t, k, etc.; s).

²⁴ Between vowels, or between a vowel and r, l (on either side).

Consonant clusters

Proto-Indo-European also had numerous consonant clusters, such as *st, *ḱs. In most cases in most languages, each consonant in a cluster develops according to the normal development given in the table above. Many consonant clusters however also show special developments in multiple languages. Some of these are given by the following table (with cases of otherwise predictable development in gray):

Table 2. Reflexes of Proto-Indo-European consonant clusters

PIE	Indo-Iranian		Balto-Slavic		Alb.	Arm.	Anatol.	Toch.	Greek		Italic	Celtic	Germanic
	Skr.	Av.	O.C.S.	Lith.			Hitt.				Latin	Old Irish	Gothic	English
									normal	C+[j]
*sr	sr	r	str	sr	rr [r]	(a)r	š(ša)r ʃʃr		rh	n/a	fr-, -br-	sr	str	str
*tw	tv	θβ	tv	tv	t	kʿ [kʰ]	ttu, ddu		s-, -ss-	n/a	p?	t	þw	thw
*dʰw	dhv	ðβ	dv	dv	d	?	tu, du				f	d	dw	dw
*dw	dv					(e)rk	tu, du				b		tw	tw
*ḱw	śv	sp	sv	šv	s	sk, š				n/a	qu [kʷ]	cu [kʷ]	ƕ [xʷ]	wh
*ǵʰw	hv		zv	žv	z
*ǵw	jv												q [kʷ]	qu [kw]
*sw	sv	xuu [xʷ]	sv	sv	v	kʿ [kʰ]	normal dev.		h	n/a	su [sw]	s	sw	sw
*sp	sp	sp [CC 1]	sp		f	sp [CC 1] / pʿ [pʰ]	normal dev.		sp [CC 1]	?	sp	f	sp [CC 2]
*st	st	st [CC 1]	st		sht [ʃt]	st [CC 1]	normal dev.		st [CC 1]	s; tt/ss[CC 3]	st		st [CC 2]
*sḱ	ch [t͡ɕʰ]; cch[CC 3]	s?	sk	š?	h	?? č`; c`[CC 3]	normal dev.		sk; [CC 1] kh [kʰ];^19 skh [skʰ] [CC 4]		sc [sk]	sc [sk]	sk [CC 2]	sh [ʃ]
*sk	sk, sc	sk, sč [CC 1]	normal dev.		?	sk [CC 1]	normal dev.
*skʷ									norm.		squ [skʷ]		sq [CC 2]
*t+t [tst]	tt; tth [CC 5]	st; sθ^17?	st		s	s?	zt, zzašt, zzazz [tst]	ss?	st		ss		ss / st
*pt	pt	ft	t?	pt	t				pt		pt	cht [xt]	ft [CC 2]
*ḱt	ṣṭ [ʂʈ]	št [ʃt]	st	št [ʃt]					kt		ct [kt]		ht [CC 2]	ght [t] [CC 2]
*kt	kt	xt	t?	kt
*kʷt									pt		ct [kt]
*ps									ps		ps	s, ss	fs	ps
*ḱs	kṣ	š			sh [ʃ]				ks		x [ks]		hs	x [ks]
*ks	kṣ^11	xš^11						(ks)
*kʷs							kʷs		ps		x [ks]
*sd	ḍ	zd	zd	zd		st					d	-t- [d]	st	st
*sdʰ	ḍh	zd	zd	zd					sth			-t- [d]	zd	d

Notes to Table 2:

1. In contrast to *s normally giving h in Avestan, Armenian and Greek.
2. Germanic spirant law: *p, *t, *k, *kʷ remain stops when preceded by another stop or *s.
3. Between vowels.
4. After (Greek) th.
5. Before an original laryngeal.

Notes for table 1 and table 2:

⁶ Before or after a (PIE) u.

⁸ Between vowels.

⁹ Before a sonorant.

¹⁰ Before secondary (post-PIE) front-vowels.

¹¹ After r, u, k, i (Ruki sound law).

¹² Before a stressed vowel.

¹⁷ Before a consonant or original laryngeal.

¹⁹ After r, l, m, n, t, d, possibly other consonants?

²¹ At the beginning of a word.

²² Before or after an obstruent (p, t, k, etc.; s).

²⁴ Between vowels, or between a vowel and r, l (on either side).

Vowels and syllabic consonants

This table shows the Proto-Indo-European vowels and syllabic consonants (as reconstructed both before and after the acceptance of laryngeal theory), and their reflexes in selected Indo-European daughter languages. Background and further details can be found in various related articles, including Proto-Indo-European phonology, the articles on the various sound laws referred to in the introduction, and the articles on the various IE proto-languages, language groups and language phonologies.

Trad. PIE	Laryng. PIE	Skr.	Av.	O.C.S.	Lith.	Arm.	Alb.	Toch.	Hitt.	Greek	Latin^18	Proto-Celtic	Gothic^19	Old English^18
														normal	umlauted^20
*e	*e, *h₁e	a		e			je, ie, e, i; ja^12	ä	e, ʔe, i	e			i; aí [ɛ]^2	e; eo^21	i; ie^21
*a	(*a^3), *h₂e			o	a	a	ha, a	ā	ha, a	a			a	æ; a;^22 ea^21	e; ie^21
*o	*h₃e					o, a	a	a, e	a	o
	*o	a; ā^4
*ə^16	*h₁^16	i	i, Ø	Ø		a, Ø		ā	Ø	e	a		a, Ø
	*h₂^16								ḫ	a
	*h₃^16								Ø	o
*-	*h₁-^17	Ø				e (a?)	Ø		a, Ø	e (o)	Ø
	*h₂-^17					a			ḫa	a
	*h₃-^17								a, ha	o
*ē	*ē, *eh₁	ā		ě	ė	i	o, ua	a/e?; ā?^8	ē, e, i	ē		ī	ē	ǣ
*ā	(*ā^3), *eh₂			a	o [oː]	a		a/o?	a, ah	ā > ē^15	ā	ā	ō		ē
*ō	*ō, *eh₃				uo	u	e	a/ā?; ū?^8	a, ā	ō		ā; ū^8
*i	*i	i		ь	i	i	i; e^10	ä	i, ī	i			i; aí [ɛ]^2	i
*ī	*ih₁	ī		i	y [iː]		i	i		ī	ī		ei [iː]	ī
	*ih₂					i or ^(j)a?^7		yā		ī or ^(j)ā?^7
	*ih₃									ī or ^(j)ō?^7
*ei	*ei, *h₁ei	ai > ē	ai > ōi, āi > aē^4		ei; ie^5	i		e	ē	ei	ī	īa; ē^6
*oi	*oi, *h₃ei			ě	ai; ie^5	e	e, ai		ē, ai	oi	ū	oe	ái	ā	ǣ
*ai	(*ai^3), *h₂ei									ai	ae	ae
*ēi	*ēi	ai; ā^8	āi; ā(i)^8	i			i		ē	ēi	ī?		ei [iː]	ī
*ōi	*ōi (*oei)			y; u^8	ai; ui^8		e, ai		ai	ōi	ō	u^8	ái	ā	ǣ
*āi	*eh₂ei			ě					ai	āi > ēi^15	ae
*u	*u	u		ъ	u	u	u; y^11	ä	u	u	u	u; o^1	u; aú [ɔ]^2	u; o^23	y
*ū	*uh₁	ū		y	ū		y; i^8	u		ū	ū				ȳ
	*uh₂					u or ^(w)a?^7		wā		ū or ^(w)ā?^7
	*uh₃									ū or ^(w)ō?^7
*eu	*eu, *h₁eu	ō	ə̄u; ao^4	ju	iau	oy	e	u		eu	ū	ūa; ō^9	iu	ēo	īe
*ou	*ou,*h₃eu			u	au		a	o, au		ou			áu	ēa
*au	(*au^3), *h₂eu					aw				au	au
*ēu	*ēu	āu		u	iau		e				ū?		iu	ēo
*ōu	*ōu						a		au	ō			áu	ēa
*m̥	*m̥	a		ę	im̃; um̃^14	am	a	äm	a, un	a	em	em, am	um	um	ym
*m̥̅	*mh₁	ā			ìm; ùm^14	ama		mā		mē	mā
	*mh₂									mā > mē^15
	*mh₃									mō
*m̥m	*m̥m	am		ьm/ъm	im; um^14	am				am	em	am
*n̥	*n̥	a		ę	iñ; uñ^14	an		än	an	a	en	en, an	un	un	yn
*n̥̄	*nh₁	ā			ìn; ùn^14	ana		nā		nē	nā
	*nh₂									nā > nē ^15
	*nh₃									nō
*n̥n	*n̥n	an		ьn/ъn	iñ; uñ^14	an				an	en	an
*l̥	*l̥	ṛ	ərə	lь/lъ	il̃; ul̃^14	al	il, li; ul, lu	äl	al	la	ol	li^24; al	ul	ul; ol^23	yl
*l̥̄	*lh₁	īr; ūr^13	arə		ìl; ùl^14	ala	al	lā		lē	lā
	*lh₂									lā > lē^15
	*lh₃									lō
*l̥l	*l̥l	ir; ur^13	ar	ьl/ъl	il; ul^14	al, la				al	el	al
*r̥	*r̥	ṛ	ərə	rь/rъ	ir̃; ur̃^14	ar	ir, ri; ur, ru	är	ar, ur	ra	or	ri^24; ar	aúr [ɔr]	ur; or^23	yr
*r̥̄	*rh₁	īr; ūr^13	arə		ìr; ùr^14	ara	ra	rā		rē	rā
	*rh₂									rā > rē^15
	*rh₃									rō
*r̥r	*r̥r	ir; ur^13	ar	ьr/ъr	ir; ur^14	ar				ar	ar	ar
Trad. PIE	Laryng. PIE	Skr.	Av.	O.C.S.	Lith.	Arm.	Alb.	Toch.	Hitt.	Greek	Latin^18	Proto-Celtic	Gothic^19	normal	umlauted^20
														Old English^18

Notes

• ¹ Before wa.
• ² Before r, h. Gothic, but not other Germanic languages, merges /e/ and /i/.
• ³ The existence of PIE non-allophonic a is disputed.
• ⁴ In open syllables (Brugmann's law).
• ⁵ Under stress.
• ⁶ Before palatal consonants.
• ⁷ The so-called breaking is disputed (typical examples are *proti-h₃kʷo- > Ved. prátīkam ~ Gk. πρόσωπον; *gʷih₃u̯o- > Ved. jīvá- ~ Arm. keank‘, Gk. ζωός; *duh₂ro- > Ved. dūrá- ~ Arm. erkar, Gk. δηρός)
• ⁸ In a final syllable.
• ⁹ Before velars and unstressed
• ¹⁰ Before ā in the following syllable.
• ¹¹ Before i in the following syllable.
• ¹² In a closed syllable.
• ¹³ In the neighbourhood of labials.
• ¹⁴ In the neighbourhood of labiovelars.
• ¹⁵ ā > ē in Attic and Ionic dialects only.
• ¹⁶ Between consonants, or at the end of a word after a consonant.
• ¹⁷ At the beginning of a word, followed by a consonant.
• ¹⁸ In initial syllables only.
• ¹⁹ In non-final syllables only.
• ²⁰ Before i, ī, or /j/ in the next syllable in Proto-Germanic (i-umlaut).
• ²¹ Before h, w, or before r, l plus a consonant ("breaking").
• ²² Before a back vowel in the next syllable (a restoration).
• ²³ Before a non-high vowel in the next syllable (a-mutation).
• ²⁴ Before a stop or m.

Examples

See the list of Proto-Indo-European roots hosted at Wiktionary.

*p

*pṓds, ~ *ped-, "foot".[1]

• Vedic Sanskrit: pā́t, pád-
• Avestan: paδa, pāδa
• Old Church Slavonic: pěšĭ, "on foot"
• Lithuanian: pėda, "foot bottom"
• Armenian: otn
• Tocharian: A pe, B pai
• Luwian: pa-da-, pa-ta-
• Ancient Greek: poús, podós
• Latin: pēs, pedis
• Celtiberian: ozas
• Gothic: fotus (*p -> f by Grimm's Law)

*t

*tréyes, "three".[1]

• Vedic Sanskrit: tráyas
• Avestan: θrāiiō
• Old Church Slavonic: trĭje
• Lithuanian: trỹs
• Albanian: tre
• Ancient Greek: treĩs
• Latin: trēs
• Old Irish: trí
• Welsh: tri
• Armenian: erekʿ
• Gothic: þreis (*t -> þ by Grimm's Law)

*ḱ

*ḱm̥tóm, "hundred" (from earlier *dk̂m̥tóm)[1]

• Vedic Sanskrit: śatám
• Younger Avestan: satəm
• Old Church Slavonic: sŭto
• Lithuanian: šim̃tas
• Tocharian: A känt, B känte
• Ancient Greek: hekatón
• Latin: centum (pronounced kentum)
• Old Irish: cét
• Welsh: cant
• Gothic: hund (from proto-Germanic *xund-)[2]

*k

*kréwh₂s, "raw flesh"[1]

• Vedic Sanskrit: kravís-, "raw meat"
• Lithuanian: kraũjas, "blood"
• Old Church Slavonic: kry, "blood"
• Ancient Greek: kréas, "meat"
• Latin: cruor, "raw blood"
• Old Irish: crú, "blood, gore"
• Old English: hrǣw, "raw"

Sound laws within PIE

A few phonological laws can be reconstructed that may have been effective prior to the final breakup of PIE by internal reconstruction.

• Sievers' law (Edgerton's law, Lindeman's option)
• Bartholomae's law
• Szemerényi's law
• Stang's law
• Siebs' law

See also

• Centum and satem languages
• Balto-Slavic languages
• Italo-Celtic
• Proto-Indo-Iranian language
• Proto-Iranian
• Proto-Greek language
• Proto-Celtic
• Proto-Germanic
• Proto-Indo-European language
• Proto-Indo-Europeans
• Kurgan hypothesis
• Indo-European languages
• List of Indo-European languages

References

1. Meier-Brügger, Michael; Gertmenian, Charles (translator) (2003). Indo-European linguistics. Berlin [u.a.]: de Gruyter. pp. 101–131. ISBN 3-11-017433-2.
2. Hock, Hans Heinrich (1986). Principles of historical linguistics. Berlin; New York: Walter de Gruyter. p. 132. ISBN 3-11-010600-0.