Indo-European sound laws

Map showing some major isoglosses between the branches of Indo-European (at around 500 BC).

  Blue: centum languages

  Red: satem languages

  Orange: languages with augment

  Green: languages with PIE *-tt- > -ss-

  Tan: languages with PIE *-tt- > -st-

  Pink: languages with instrumental, dative and ablative plurals (and some singulars and duals) in *-m- rather than *-bh-

Template:PIE notice As the Proto-Indo-European language (PIE) broke up, its sound system diverged as well, according to various sound laws in 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 are 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; and merging of voiced and breathy-voiced stops, and /a/ and /o/, in various "northern" languages. Bartholomae's law in Indo-Iranian, and Sievers' 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 are 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 is Greek, Indo-Iranian, and Armenian; among the 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]16	p; f17	p			h; w	p			pt	p	Ø		f; b [β]3	f; v, f8
*t	t; th [t̪ʰ]16	t; θ17	t			tʿ [tʰ]	t; z [ts]5	t; c [c]5	t	s; tt/ss	t	t	th [θ]	þ [θ]; d [ð];3 t4	th; d;3 t4
*ḱ	ś [ɕ]	s		š [ʃ]	th [θ]; k9	s	k	k; ś [ɕ]9	k		c [k]	c [k]	ch [x]	h; g [ɣ]3	h; Ø;8 y3
*k	k; c [t͡ɕ];5 kh [kʰ]16	k; c [tʃ];5 x17	k; č [tʃ];5 c [ts]10	k	k	kʿ [kʰ]
*kʷ					k; s;5 q [c]10		ku		p; t;5 k6		qu [kʷ]; c [k]7			ƕ [ʍ]; gw, w3	wh; w3
*b	b; bh16	b; β18	b			p			b	pt	b	b [b]	-[β]-	p
*d	d; dh16	d; δ18	d		d; dh [ð]8	t		ts; ś [ɕ]5	d	z [zd] > [z]	d	d [d]	-[ð]-	t
*ǵ	j [d͡ʑ]; h [ɦ]16	z		ž [ʒ]	dh [ð]; g9	c [ts]	k	k; ś [ɕ]9	g		g	g [ɡ]	-[ɣ]-	k	c / k; ch10
*g	g; j [d͡ʑ];5 gh;16 h [ɦ]16,5	g; j [dʒ];5 γ18	g; ž [ʒ];5 dz10	g	g	k
*gʷ					g; z;5 gj [ɟ]10		ku		b; d;5 g6		u [w > v]; gu [ɡʷ]15	b [b]	-[β]-	q [kʷ]	qu
*bʰ	bh [bʱ]	b; β18	b			b; w8	p		ph [pʰ]	pt	f;21 b			b [b]; b [β];8 f13	b; v / f24
*dʰ	dh [dʱ]	d; δ18	d				t	t; c [c]5	th [tʰ]	tt/ss	f;21 d; b14	d [d]	-[ð]-	d; d [ð];8 þ13	d
*ǵʰ	h [ɦ]	z		ž [ʒ]	dh [ð]; d9	j [dz]; z8	k	k; ś [ɕ]5	kh [kʰ]		h; h / g9	g [ɡ]	-[ɣ]-	g; g [ɣ];8 g [x]13	g; y / w24
*gʰ	gh [ɡʱ]; h [ɦ]5	g; j [dʒ];5 γ18	g; ž [ʒ];5 dz10	g	g	g; ǰ [dʒ]5
*gʷʰ					g; z;5 gj [ɟ]10		ku		ph [pʰ]; th [tʰ];5 kh [kʰ]6		f;21 g / u [w];8 gu [ɡʷ]15			g; b;21 w;8 gw15	g; b;21 w8
*s	s	h [h, x]	s		sh [ʃ]; gj [ɟ];12 h8	h; Ø8	š [s]	s; ṣ [ʂ]	h;21 s;22, 13 Ø;8 [¯]23	i	s; r8	s [s]	-[h]-	s; z3	s; r3
	ṣ [ʂ]11	š [ʃ]11	x [x]11	š [ʃ]11
*m	m									in	m	m [m]	-[w̃]-	m
*-m13	m		˛ [˜]	n		Ø		n		--	m	n		Ø
*n	n		n; ˛ [˜]13	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
*i̯	y [j]		j [j]		gj [ɟ]; Ø	Ø	y [j]		z [zd] > [z] / h; Ø 8	?i	i [j]; Ø 8	Ø		j	y
*u̯	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:

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]
*sp	sp	sp	sp		f	sp / pʿ [pʰ]	normal dev.		sp	?	sp	f	sp
*st	st	st	st		sht [ʃt]	st	normal dev.		st	s; tt/ss	st		st
*sḱ	ch [t͡ɕʰ]; cch	s?	sk	š?	h	?? č`; c`	normal dev.		sk; kh [kʰ];19 skh [skʰ]20		sc [sk]	sc [sk]	sk	sh [ʃ]
*sk	sk, sc	sk, sč	normal dev.		?	sk	normal dev.
*skʷ									norm.		squ [skʷ]		sq
*t+t [tst]	tt; tth16	st; sθ17?	st		s	s?	zt [tst]	ss?	st		ss		ss / st
*pt	pt	ft			t								ft
*ḱt	ṣṭ [ʂʈ]	št [ʃt]										cht [xt]	ht	ght [t]
*kt	kt	xt
*kʷt
*ps														ps
*ḱs	kṣ	š			sh [ʃ]				ks		x [ks]			x [ks]
*ks	kṣ11	xš11						(ks)
*kʷs							kʷs		ps
PIE	Skr.	Av.	O.C.S.	Lith.	Alb.	Arm.	Hitt.	Toch.	Greek	Greek+/j/	Latin	Old Irish	Gothic	English

See also Germanic spirant law, Bartholomae's law.

Notes:

• ² In contrast to *s normally giving h in Avestan, Armenian and Greek.
• ³ Following an unstressed vowel (Verner's law).
• ⁴ After a (PIE) stop or s.
• ⁵ Before a (PIE) front vowel (i, e).
• ⁶ Before or after a (PIE) u.
• ⁷ Before or after a (PIE) o, 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.
• ¹³ At the end of a word.
• ¹⁴ After u, r or before r, l.
• ¹⁵ After n.
• ¹⁶ Before an original laryngeal.
• ¹⁷ Before a consonant or original laryngeal.
• ¹⁸ In Younger Avestan, after a vowel.
• ¹⁹ After r, l, m, n, t, d, possibly other consonants?
• ²⁰ After (Greek) th.
• ²¹ At the beginning of a word.
• ²² Before or after an obstruent (p, t, k, etc.; s).
• ²³ Before or after a resonant (r, l, m, n).
• 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	Latin18	Proto-Celtic	Gothic19	Old English18
														normal	umlauted20
*e	*e, *h₁e	a		e			je, ie, e, i; ja12	ä	e, i	e			i; aí [ɛ]2	e; eo21	i; ie21
*a	(*a3), *h₂e			o	a	a	ha, a	ā	ha, a	a			a	æ; a;22 ea21	e; ie21
*o	*h₃e					o, a	a	a, e	a	o
	*o	a; ā4
*ə16	*h₁16	i	i, Ø	Ø		a, Ø		ā	a	e	a		a, Ø
	*h₂16								h	a
	*h₃16									o
*-	*h₁-17	Ø				e (a?)	Ø		a	e (o)	Ø
	*h₂-17					a			ha	a
	*h₃-17								a, ha	o
*ē	*ē, *eh₁	ā		ě	ė	i	o, ua	a/e?; ā?8	e, i	ē		ī	ē	ǣ
*ā	(*ā3), *eh₂			a	o [oː]	a		a/o?	a, ah	ā > ē15	ā	ā	ō		ē
*ō	*ō, *eh₃				uo	u	e	a/ā?; ū?8	a	ō		ā; ū8
*i	*i	i		ь	i	i	i; e10	ä	i	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 > aē4		ei; ie5	i		e	ei	ei	ī	īa; ē6
*oi	*oi, *h₃ei			ě	ai; ie5	e	e, ai		ay	oi	ū	oe	ái	ā	ǣ
*ai	(*ai3), *h₂ei									ai	ae	ae
*ēi	*ēi	āi; ā8	āi; ā(i)8	i			i			ēi	ī?		ei [iː]	ī
*ōi	*ōi (*oei)			y; u8	ai; ui8		e, ai		ai	ōi	ō	u8	ái	ā	ǣ
*āi	*eh₂ei			ě						āi > ēi15	ae
*u	*u	u		ъ	u	u	u; y11	ä	u	u	u	u; o1	u; aú [ɔ]2	u; o23	y
*ū	*uh₁	ū		y	ū		y; i8	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; ao4	ju	iau	oy	e	u		eu	ū	ūa; ō9	iu	ēo	īe
*ou	*ou,*h₃eu			u	au		a	o, au		ou			áu	ēa
*au	(*au3), *h₂eu					aw				au	au
*ēu	*ēu	āu		u	iau		e				ū?		iu	ēo
*ōu	*ōu						a			ō			áu	ēa
*m̥	*m̥	a		ę	im̃; um̃14	am	a	äm	am	a	em	em, am	um	um	ym
*m̥̅	*mh₁	ā			ìm; ùm14	ama		mā		mē	mā
	*mh₂									mā > mē15
	*mh₃									mō
*m̥m	*m̥m	am		ьm/ъm	im; um14	am				am	em	am
*n̥	*n̥	a		ę	iñ; uñ14	an		än	an	a	en	en, an	un	un	yn
*n̥̄	*nh₁	ā			ìn; ùn14	ana		nā		nē	nā
	*nh₂									nā > nē 15
	*nh₃									nō
*n̥n	*n̥n	an		ьn/ъn	iñ; uñ14	an				an	en	an
*l̥	*l̥	ṛ	ərə	lь/lъ	il̃; ul̃14	al	il, li; ul, lu	äl	al	la	ol	li24; al	ul	ul; ol23	yl
*l̥̄	*lh₁	īr; ūr13	arə		ìl; ùl14	ala	al	lā		lē	lā
	*lh₂									lā > lē15
	*lh₃									lō
*l̥l	*l̥l	ir; ur13	ar	ьl/ъl	il; ul14	al, la				al	el	al
*r̥	*r̥	ṛ	ərə	rь/rъ	ir̃; ur̃14	ar	ir, ri; ur, ru	är	ar	ra	or	ri24; ar	aúr [ɔr]	ur; or23	yr
*r̥̄	*rh₁	īr; ūr13	arə		ìr; ùr14	ara	ra	rā		rē	rā
	*rh₂									rā > rē15
	*rh₃									rō
*r̥r	*r̥r	ir; ur13	ar	ьr/ъr	ir; ur14	ar				ar	ar	ar
Trad. PIE	Laryng. PIE	Skr.	Av.	O.C.S.	Lith.	Arm.	Alb.	Toch.	Hitt.	Greek	Latin18	Proto-Celtic	Gothic19	normal	umlauted20
														Old English18

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".

• Vedic Sanskrit: pád-
• Avestan: pâdha
• Slovenian: pòd, "floor"
• Lithuanian: pėda, "foot bottom"
• Armenian: otn
• Tocharian: A pe, B pai
• Luwian: pa-da-, pa-ta-
• Greek: poús, podós
• Latin: pēs, pedis
• Scottish Gaelic: edh, "pace"
• Gothic: fotus (*p -> f by Grimm's Law)

*t

*tréyes, "three".

• Vedic Sanskrit: tráyas
• OCS: trьje
• Lithuanian: trỹs
• Albanian: tre
• Greek: treĩs
• Latin: trēs
• Irish: trí
• Arm.ere
• Old Norse: þrir (*t -> þ by Grimm's Law)

*ḱ

*ḱm̥tóm, "hundred" (from earlier *dk̂m̥tóm)

• Vedic Sanskrit: śatám
• Later Avestan: satəm
• OCS: sьto
• Lithuanian: šimtas
• Tocharian: A känt, B känte
• Greek: hekatón
• Latin: centum (i.e., kentum)
• Welsh: cant
• Gothic: hund- (from proto-Germanic *xund)

*k

*kreuh₂, "raw flesh"

• Vedic Sanskrit: kravíṣ-, "raw meat"
• Lithuanian: kraûjas, "blood"
• OCS: krьvь, "blood"
• Greek: kréas, "meat"
• Latin: cruor, "raw blood"
• Irish: cró, "blood, gore"
• Old English: hrō, "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-Satem isogloss
• 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