Indo-European sound laws - AbsoluteAstronomy.com

Proto-Indo-European language

The Proto-Indo-European language is the reconstructed common ancestor of the Indo-European languages, spoken by the Proto-Indo-Europeans...

(PIE) broke up, its sound system diverged as well, according to various sound law

Sound change

Sound change includes any processes of language change that affect pronunciation or sound system structures...

s in the daughter languages

Indo-European languages

The Indo-European languages are a family of several hundred related languages and dialects, including most major current languages of Europe, the Iranian plateau, and South Asia and also historically predominant in Anatolia...

.

Especially notable is the palatalization that produced the Satem languages, along with the associated ruki sound law

Ruki sound law

Ruki refers to a sound change in Balto-Slavic, Albanian, Armenian, and Indo-Iranian, wherein an original phoneme changed into after the consonants , , and the semi-vowels , , or:...

. Other notable changes are Grimm's law

Grimm's law

Grimm's law , named for Jacob Grimm, is a set of statements describing the inherited Proto-Indo-European stops as they developed in Proto-Germanic in the 1st millennium BC...

and Verner's law

Verner's law

Verner's law, stated by Karl Verner in 1875, describes a historical sound change in the Proto-Germanic language whereby voiceless fricatives *f, *þ, *s, *h, *hʷ, when immediately following an unstressed syllable in the same word, underwent voicing and became respectively the fricatives *b, *d, *z,...

in Proto-Germanic; an independent change similar to Grimm's law in Armenian

Armenian language

The Armenian language is an Indo-European language spoken by the Armenian people. It is the official language of the Republic of Armenia as well as in the region of Nagorno-Karabakh. The language is also widely spoken by Armenian communities in the Armenian diaspora...

; loss of prevocalic *p- in Proto-Celtic; Brugmann's law

Brugmann's law

Brugmann's law, named for Karl Brugmann, states that Proto-Indo-European in non-final syllables became *ā in open syllables in Indo-Iranian. Everywhere else the outcome was *ǎ, the same as the reflexes of PIE *e and *a...

in Proto-Indo-Iranian

Proto-Indo-Iranian language

Proto-Indo-Iranian is the reconstructed proto-language of the Indo-Iranian branch of Indo-European. Its speakers, the hypothetical Proto-Indo-Iranians, are assumed to have lived in the late 3rd millennium BC, and are usually connected with the early Andronovo archaeological...

; Winter's law and Hirt's law in Balto-Slavic

Balto-Slavic languages

The Balto-Slavic language group traditionally comprises Baltic and Slavic languages, belonging to the Indo-European family of languages. Baltic and Slavic languages share several linguistic traits not found in any other Indo-European branch, which points to the period of common development...

; and merging of voiced and breathy-voiced stops, and /a/ and /o/, in various "northern" languages. Bartholomae's law

Bartholomae's law

Bartholomae's law is an early Indo-European sound law affecting the Indo-Iranian family. It states that in a cluster of two or more obstruents , any one of which is a voiced aspirated stop anywhere in the sequence, the whole cluster becomes voiced and aspirated...

in Indo-Iranian, and Sievers' law

Sievers' law

Sievers' law in Indo-European linguistics accounts for the pronunciation of a consonant cluster with a glide before a vowel as it was affected by the phonetics of the preceding syllable. Specifically it refers to the alternation between and , and possibly and , in Indo-European languages...

in Proto-Germanic

Proto-Germanic language

Proto-Germanic , or Common Germanic, as it is sometimes known, is the unattested, reconstructed proto-language of all the Germanic languages, such as modern English, Frisian, Dutch, Afrikaans, German, Luxembourgish, Danish, Norwegian, Icelandic, Faroese, and Swedish.The Proto-Germanic language is...

and (to some extent) various other branches, may or may not have been a common Indo-European feature. A number of innovations, both phonological

Phonology

Phonology is, broadly speaking, the subdiscipline of linguistics concerned with the sounds of language. That is, it is the systematic use of sound to encode meaning in any spoken human language, or the field of linguistics studying this use...

and morphological

Morphology (linguistics)

In linguistics, morphology is the identification, analysis and description, in a language, of the structure of morphemes and other linguistic units, such as words, affixes, parts of speech, intonation/stress, or implied context...

, represent areal features common to the Italic

Italic languages

The Italic subfamily is a member of the Indo-European language family. It includes the Romance languages derived from Latin , and a number of extinct languages of the Italian Peninsula, including Umbrian, Oscan, Faliscan, and Latin.In the past various definitions of "Italic" have prevailed...

and Celtic

Celtic languages

The Celtic languages are descended from Proto-Celtic, or "Common Celtic"; a branch of the greater Indo-European language family...

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

Grassmann's Law

Grassmann's law, named after its discoverer Hermann Grassmann, is a dissimilatory phonological process in Ancient Greek and Sanskrit which states that if an aspirated consonant is followed by another aspirated consonant in the next syllable, the first one loses the aspiration...

in Greek and Indo-Iranian, and weakening of pre-vocalic /s/ to /h/ in Greek, Iranian and Armenian.
Note - these draft tables need to be completed, verified, and the allophones explained.

Consonants

**Proto-Indo-European consonants and their reflexes in selected Indo-European daughter languages**
PIE	Skr. Sanskrit Sanskrit , is a historical Indo-Aryan language and the primary liturgical language of Hinduism, Jainism and Buddhism.Buddhism: besides Pali, see Buddhist Hybrid Sanskrit Today, it is listed as one of the 22 scheduled languages of India and is an official language of the state of Uttarakhand...	Av. Avestan language Avestan is an East Iranian language known only from its use as the language of Zoroastrian scripture, i.e. the Avesta, from which it derives its name...	O.C.S. Old Church Slavonic Old Church Slavonic or Old Church Slavic was the first literary Slavic language, first developed by the 9th century Byzantine Greek missionaries Saints Cyril and Methodius who were credited with standardizing the language and using it for translating the Bible and other Ancient Greek...	Lith. Lithuanian language Lithuanian is the official state language of Lithuania and is recognized as one of the official languages of the European Union. There are about 2.96 million native Lithuanian speakers in Lithuania and about 170,000 abroad. Lithuanian is a Baltic language, closely related to Latvian, although they...	Alb. Albanian language Albanian is an Indo-European language spoken by approximately 7.6 million people, primarily in Albania and Kosovo but also in other areas of the Balkans in which there is an Albanian population, including western Macedonia, southern Montenegro, southern Serbia and northwestern Greece...	Arm. Armenian language The Armenian language is an Indo-European language spoken by the Armenian people. It is the official language of the Republic of Armenia as well as in the region of Nagorno-Karabakh. The language is also widely spoken by Armenian communities in the Armenian diaspora...	Hitt. Hittite language Hittite is the extinct language once spoken by the Hittites, a people who created an empire centred on Hattusa in north-central Anatolia...	Toch. Tocharian languages Tocharian or Tokharian is an extinct branch of the Indo-European language family. The name is taken from the people known to the Greeks as the Tocharians . These are sometimes identified with the Yuezhi and the Kushans. The term Tokharistan usually refers to 1st millennium Bactria, which the...	Greek Greek language Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...	Greek Greek language Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;... +/y/	Latin Latin Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...	Old Irish	Gothic Gothic language Gothic is an extinct Germanic language that was spoken by the Goths. It is known primarily from the Codex Argenteus, a 6th-century copy of a 4th-century Bible translation, and is the only East Germanic language with a sizable Text corpus...	English
	; ¹⁶	; ¹⁷				; ¹						; [x]²	; [β]³	; ⁸
	normal development of /s/+/p/					normal development of /s/+/p/
	; ¹⁶	; ¹⁷				[tʰ]	; [ts]⁵	; [c]⁵		; /¹		; [θ]⁸	[θ]; [ð];³ ⁴	; ;³ ⁴
	; ¹⁶	; ¹⁷?				?	[tst]	?					or
	normal development of /s/+/t/				[ʃt]	normal development of /s/+/t/
	[ɕ]			[ʃ]	[θ]; ⁹			; [ɕ]⁹			[k]	[k]; [x]⁸	; [ɣ]³	; ;⁸ ³
	; [tʃ];⁵ ¹⁶	; [tʃ];⁵ ¹⁷	; [tʃ];⁵ [ts]¹⁰			[kʰ]					[k]		; [ɣ]³	; ;⁸ ³
	; [tʃ];⁵ ¹⁶	; [tʃ];⁵ ¹⁷	; [tʃ];⁵ [ts]¹⁰		; ;⁵ [c]¹⁰	[kʰ]			; ;⁵ ⁶		[kʷ]; [k]⁷		[ʍ]; ³	; ³
	; ¹	?	?	?		?? ; ¹	normal dev. of /s/+/ḱ/		sk; kh;¹⁹ skh²⁰		[sk]			[ʃ]
	normal development of /s/+/k/				?	normal development of /s/+/k/			sk; kh;¹⁹ skh²⁰		[sk]
	normal development of /s/+/kʷ/				?	normal development of /s/+/kʷ/					[skʷ]	[sk]
	; ¹⁶	; ¹⁸										[b]; [β]⁸
	; ¹⁶	; ¹⁸			; [ð]⁸			; [ɕ]⁵		[zd > dz > z]		[d]; [ð]⁸
	[dʒ]; [ɦ]¹⁶			[ʒ]	[ð]; ⁹	[ts]		; [ɕ]⁹				[ɡ]; [ɣ]⁸		; ¹⁰
	; [dʒ];⁵ ;¹⁶ [ɦ]^16,5	; [dʒ];⁵ ¹⁸	; [ʒ];⁵ ¹⁰									[ɡ]; [ɣ]⁸		; ¹⁰
	; [dʒ];⁵ ;¹⁶ [ɦ]^16,5	; [dʒ];⁵ ¹⁸	; [ʒ];⁵ ¹⁰		; ;⁵ [ɟ]¹⁰				; ;⁵ ⁶		[w > v]; [ɡʷ]¹⁵	[b]; [β]⁸	[kʷ]
	[bʱ]	; ¹⁸				; ⁸			[pʰ]		;²¹	[b]; [β]⁸	[b]; [β];⁸ ¹³	; ²⁴
	[dʱ]	; ¹⁸						; [c]⁵	[tʰ]	/	;²¹ ; ¹⁴	[d]; [ð]⁸	; [ð];⁸ ¹³
	[ɦ]			[ʒ]	[ð]; ⁹	[dz]; ⁸		; [ɕ]⁵	[kʰ]		; / ⁹	[ɡ]; [ɣ]⁸	; [ɣ];⁸ [x]¹³	; ²⁴
	[ɡʱ]; [ɦ]⁵	; [dʒ];⁵ ¹⁸	; [ʒ];⁵ ¹⁰			; [dʒ]⁵			[kʰ]		; / ⁹		; [ɣ];⁸ [x]¹³	; ²⁴
	[ɡʱ]; [ɦ]⁵	; [dʒ];⁵ ¹⁸	; [ʒ];⁵ ¹⁰		; ;⁵ [ɟ]¹⁰	; [dʒ]⁵			[pʰ]; [tʰ];⁵ [kʰ]⁶		;²¹ / [w];⁸ [ɡʷ]¹⁵		; ;²¹ ;⁸ ¹⁵	; ;²¹ ;⁸
		[h, x]; ²			[ʃ]; [ɟ];¹² ⁸	; ;² ⁸	[s]	; [ʂ]	;²¹ ;^{22, 13} ;⁸ [¯]²³		; ⁸	[s]; [h]⁸	; ³	; ³
	[ʂ]¹¹	[ʃ]¹¹	[x]¹¹	[ʃ]¹¹	[ʃ]; [ɟ];¹² ⁸	; ;² ⁸	[s]	; [ʂ]	;²¹ ;^{22, 13} ;⁸ [¯]²³		; ⁸	[s]; [h]⁸	; ³	; ³
												[m]; [w̃]⁸
13			[˜]							--
			; [˜]¹³					; [ɲ]
	(dial. )				; [ɫ]⁸	/ [ɫ > ɣ]
					[ɾ]; [r]⁸
	[j]		[j]		[ɟ];		[j]		[zd > dz > z] / ; ⁸	?	[j]; ⁸
	[ʋ]	[w]		[ʋ]		/					[w > v]	; ⁸
PIE	Skr. Sanskrit Sanskrit , is a historical Indo-Aryan language and the primary liturgical language of Hinduism, Jainism and Buddhism.Buddhism: besides Pali, see Buddhist Hybrid Sanskrit Today, it is listed as one of the 22 scheduled languages of India and is an official language of the state of Uttarakhand...	Av. Avestan language Avestan is an East Iranian language known only from its use as the language of Zoroastrian scripture, i.e. the Avesta, from which it derives its name...	O.C.S. Old Church Slavonic Old Church Slavonic or Old Church Slavic was the first literary Slavic language, first developed by the 9th century Byzantine Greek missionaries Saints Cyril and Methodius who were credited with standardizing the language and using it for translating the Bible and other Ancient Greek...	Lith. Lithuanian language Lithuanian is the official state language of Lithuania and is recognized as one of the official languages of the European Union. There are about 2.96 million native Lithuanian speakers in Lithuania and about 170,000 abroad. Lithuanian is a Baltic language, closely related to Latvian, although they...	Alb. Albanian language Albanian is an Indo-European language spoken by approximately 7.6 million people, primarily in Albania and Kosovo but also in other areas of the Balkans in which there is an Albanian population, including western Macedonia, southern Montenegro, southern Serbia and northwestern Greece...	Arm. Armenian language The Armenian language is an Indo-European language spoken by the Armenian people. It is the official language of the Republic of Armenia as well as in the region of Nagorno-Karabakh. The language is also widely spoken by Armenian communities in the Armenian diaspora...	Hitt. Hittite language Hittite is the extinct language once spoken by the Hittites, a people who created an empire centred on Hattusa in north-central Anatolia...	Toch. Tocharian languages Tocharian or Tokharian is an extinct branch of the Indo-European language family. The name is taken from the people known to the Greeks as the Tocharians . These are sometimes identified with the Yuezhi and the Kushans. The term Tokharistan usually refers to 1st millennium Bactria, which the...	Greek Greek language Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...	Greek Greek language Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;... +/y/	Latin Latin Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...	Old Irish	Gothic Gothic language Gothic is an extinct Germanic language that was spoken by the Goths. It is known primarily from the Codex Argenteus, a 6th-century copy of a 4th-century Bible translation, and is the only East Germanic language with a sizable Text corpus...	English

Notes:

¹ After a vowel.
² Before a plosive .
³ Following an unstressed vowel (Verner's law
Verner's law
Verner's law, stated by Karl Verner in 1875, describes a historical sound change in the Proto-Germanic language whereby voiceless fricatives *f, *þ, *s, *h, *hʷ, when immediately following an unstressed syllable in the same word, underwent voicing and became respectively the fricatives *b, *d, *z,...

).
⁴ After a (PIE) stop or .
⁵ Before a (PIE) front vowel .
⁶ Before or after a (PIE) .
⁷ Before or after a (PIE) .
⁸ Between vowels.
⁹ Before a sonorant
Sonorant
In phonetics and phonology, a sonorant is a speech sound that is produced without turbulent airflow in the vocal tract; fricatives and plosives are not sonorants. Vowels are sonorants, as are consonants like and . Other consonants, like or , restrict the airflow enough to cause turbulence, and...

.
¹⁰ Before secondary (post-PIE) front-vowels.
¹¹ After (Ruki sound law
Ruki sound law
Ruki refers to a sound change in Balto-Slavic, Albanian, Armenian, and Indo-Iranian, wherein an original phoneme changed into after the consonants , , and the semi-vowels , , or:...

).
¹² Before a stressed vowel.
¹³ At the end of a word.
¹⁴ After or before .
¹⁵ After .
¹⁶ Before an original laryngeal.
¹⁷ Before a consonant or original laryngeal.
¹⁸ In Younger Avestan, after a vowel.
¹⁹ After , possibly other consonants?
²⁰ After (Greek) .
²¹ At the beginning of a word.
²² Before or after an obstruent .
²³ Before or after a resonant .
²⁴ Between vowels, or between a vowel and (on either side).

Vowels and syllabic consonants

**Proto-Indo-European vowels and syllabic consonants, and their reflexes in the Indo-European daughter languages**
Trad. PIE	Laryng. PIE Laryngeal theory The laryngeal theory is a generally accepted theory of historical linguistics which proposes the existence of one, or a set of three , consonant sounds termed "laryngeals" that appear in most current reconstructions of the Proto-Indo-European language...	Skr. Sanskrit Sanskrit , is a historical Indo-Aryan language and the primary liturgical language of Hinduism, Jainism and Buddhism.Buddhism: besides Pali, see Buddhist Hybrid Sanskrit Today, it is listed as one of the 22 scheduled languages of India and is an official language of the state of Uttarakhand...	Av. Avestan language Avestan is an East Iranian language known only from its use as the language of Zoroastrian scripture, i.e. the Avesta, from which it derives its name...	O.C.S. Old Church Slavonic Old Church Slavonic or Old Church Slavic was the first literary Slavic language, first developed by the 9th century Byzantine Greek missionaries Saints Cyril and Methodius who were credited with standardizing the language and using it for translating the Bible and other Ancient Greek...	Lith. Lithuanian language Lithuanian is the official state language of Lithuania and is recognized as one of the official languages of the European Union. There are about 2.96 million native Lithuanian speakers in Lithuania and about 170,000 abroad. Lithuanian is a Baltic language, closely related to Latvian, although they...	Arm. Armenian language The Armenian language is an Indo-European language spoken by the Armenian people. It is the official language of the Republic of Armenia as well as in the region of Nagorno-Karabakh. The language is also widely spoken by Armenian communities in the Armenian diaspora...	Alb. Albanian language Albanian is an Indo-European language spoken by approximately 7.6 million people, primarily in Albania and Kosovo but also in other areas of the Balkans in which there is an Albanian population, including western Macedonia, southern Montenegro, southern Serbia and northwestern Greece...	Toch. Tocharian languages Tocharian or Tokharian is an extinct branch of the Indo-European language family. The name is taken from the people known to the Greeks as the Tocharians . These are sometimes identified with the Yuezhi and the Kushans. The term Tokharistan usually refers to 1st millennium Bactria, which the...	Hitt. Hittite language Hittite is the extinct language once spoken by the Hittites, a people who created an empire centred on Hattusa in north-central Anatolia...	Greek Greek language Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...	Latin Latin Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and... ¹⁸	Proto-Celtic	Gothic Gothic language Gothic is an extinct Germanic language that was spoken by the Goths. It is known primarily from the Codex Argenteus, a 6th-century copy of a 4th-century Bible translation, and is the only East Germanic language with a sizable Text corpus... ¹⁹
							; ¹²						; [ɛ]²
	3),

		; ⁴
¹⁶	16
	16
	16
	17
	17
	17
								?; ?⁸
	3),				[oː]			?		¹⁵
								?; ?⁸				; ⁸
							; ¹⁰						; [ɛ]²
					[iː]								[iː]
						or ?⁷				or ?⁷
						or ?⁷				or ?⁷
			, ⁴		; ⁵							; ⁶
					; ⁵
	3),				; ⁵
		; ⁸	; ⁸								?		[iː]
				; ⁸	; ⁸							⁸
										¹⁵
							; ¹¹					; ¹	; [ɔ]²
							; ⁸
						or ?⁷				or ?⁷
						or ?⁷				or ?⁷
			; ⁴									; ⁹

	3),
											?

					; ¹⁴
					; ¹⁴
										¹⁵

					; ¹⁴
					; ¹⁴
					; ¹⁴
										¹⁵

					; ¹⁴
					; ¹⁴
		; ¹³			; ¹⁴
										¹⁵

		; ¹³			; ¹⁴
					; ¹⁴
		; ¹³			; ¹⁴
										¹⁵

		; ¹³			; ¹⁴
Trad. PIE	Laryng. PIE Laryngeal theory The laryngeal theory is a generally accepted theory of historical linguistics which proposes the existence of one, or a set of three , consonant sounds termed "laryngeals" that appear in most current reconstructions of the Proto-Indo-European language...	Skr. Sanskrit Sanskrit , is a historical Indo-Aryan language and the primary liturgical language of Hinduism, Jainism and Buddhism.Buddhism: besides Pali, see Buddhist Hybrid Sanskrit Today, it is listed as one of the 22 scheduled languages of India and is an official language of the state of Uttarakhand...	Av. Avestan language Avestan is an East Iranian language known only from its use as the language of Zoroastrian scripture, i.e. the Avesta, from which it derives its name...	O.C.S. Old Church Slavonic Old Church Slavonic or Old Church Slavic was the first literary Slavic language, first developed by the 9th century Byzantine Greek missionaries Saints Cyril and Methodius who were credited with standardizing the language and using it for translating the Bible and other Ancient Greek...	Lith. Lithuanian language Lithuanian is the official state language of Lithuania and is recognized as one of the official languages of the European Union. There are about 2.96 million native Lithuanian speakers in Lithuania and about 170,000 abroad. Lithuanian is a Baltic language, closely related to Latvian, although they...	Arm. Armenian language The Armenian language is an Indo-European language spoken by the Armenian people. It is the official language of the Republic of Armenia as well as in the region of Nagorno-Karabakh. The language is also widely spoken by Armenian communities in the Armenian diaspora...	Alb. Albanian language Albanian is an Indo-European language spoken by approximately 7.6 million people, primarily in Albania and Kosovo but also in other areas of the Balkans in which there is an Albanian population, including western Macedonia, southern Montenegro, southern Serbia and northwestern Greece...	Toch. Tocharian languages Tocharian or Tokharian is an extinct branch of the Indo-European language family. The name is taken from the people known to the Greeks as the Tocharians . These are sometimes identified with the Yuezhi and the Kushans. The term Tokharistan usually refers to 1st millennium Bactria, which the...	Hitt. Hittite language Hittite is the extinct language once spoken by the Hittites, a people who created an empire centred on Hattusa in north-central Anatolia...	Greek Greek language Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...	Latin Latin Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and... ¹⁸	Proto-Celtic	Gothic Gothic language Gothic is an extinct Germanic language that was spoken by the Goths. It is known primarily from the Codex Argenteus, a 6th-century copy of a 4th-century Bible translation, and is the only East Germanic language with a sizable Text corpus... ¹⁹

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
Brugmann's law
Brugmann's law, named for Karl Brugmann, states that Proto-Indo-European in non-final syllables became *ā in open syllables in Indo-Iranian. Everywhere else the outcome was *ǎ, the same as the reflexes of PIE *e and *a...

).
⁵ Under stress.
⁶ Before palatal consonants.
⁷ The so-called breaking is disputed (typical examples are > Ved. prátīkam ~ Gk. ; > Ved. jīvá- ~ Arm. keank‘, Gk. ; > Ved. dūrá- ~ Arm. erkar, Gk. )
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.

Examples

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

, ~ , "foot".

Vedic Sanskrit: pád-
Avestan: pâdha
Slovenian: pòd, "floor"
Lithuanian: pėda, "foot bottom"
Armenian: otn
Tocharian: A pe, B pai
Luwian
Luwian language
Luwian is an extinct language of the Anatolian branch of the Indo-European language family. Luwian is closely related to Hittite, and was among the languages spoken during the second and first millennia BC by population groups in central and western Anatolia and northern Syria...

: pa-da-, pa-ta-
Greek: poús, podós
Latin: pēs, pedis
Scottish Gaelic: edh, "pace"
Gothic: fotus (*p -> f by Grimm's Law)

, "three".

Vedic Sanskrit: tráyas
OCS: trьje
Lithuanian: trỹs
Albanian: tre
Greek: treĩs
Latin: trēs
Irish: tri
Old Norse
Old Norse
Old Norse is a North Germanic language that was spoken by inhabitants of Scandinavia and inhabitants of their overseas settlements during the Viking Age, until about 1300....

: þrir (*t -> þ by Grimm's Law)

, "hundred" (from earlier )

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)

, "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

Internal reconstruction

Internal reconstruction is a method of recovering information about a language's past from the characteristics of the language at a later date...

Sievers' law
Sievers' law
Sievers' law in Indo-European linguistics accounts for the pronunciation of a consonant cluster with a glide before a vowel as it was affected by the phonetics of the preceding syllable. Specifically it refers to the alternation between and , and possibly and , in Indo-European languages...

(Edgerton's law, Lindeman's option)
Bartholomae's law
Bartholomae's law
Bartholomae's law is an early Indo-European sound law affecting the Indo-Iranian family. It states that in a cluster of two or more obstruents , any one of which is a voiced aspirated stop anywhere in the sequence, the whole cluster becomes voiced and aspirated...
Szemerényi's law
Szemerényi's law
Szemerényi's law is a Proto-Indo-European phonological rule, named after Hungarian linguist Oswald Szemerényi, according to which word-final clusters of vowels , resonants and of either */s/ or */h₂/ are simplified by dropping the word-final fricative , with compensatory lengthening of the...
Stang's law
Stang's law
Stang's law is a Proto-Indo-European phonological rule named after Norwegian linguist Christian Stang. The law governs the word-final sequences of a vowel, followed by a laryngeal or a semivowel */y/ or */w/, followed by a nasal, and according to the law those sequences are simplified in a way that...
Siebs' law
Siebs' law
Siebs' law is a Proto-Indo-European phonological rule named after the German linguist Theodor Siebs. According to this law, if an s-mobile is added to a root that starts with a voiced or aspirated stop, that stop is devoiced.Compare:-Discussion:...

Consonants

Vowels and syllabic consonants

Examples

Sound laws within PIE

See also