Proto-Indo-European (PIE) is the theorized common ancestor of the Indo-European language family. Its proposed features have been derived by linguistic reconstruction from documented Indo-European languages. No direct record of Proto-Indo-European exists. Far more work has gone into reconstructing PIE than any other proto-language, and it is the best understood of all proto-languages of its age. The majority of linguistic work during the 19th century was devoted to the reconstruction of PIE or its daughter proto-languages (such as Proto-Germanic and Proto-Indo-Iranian), and many of the modern techniques of linguistic reconstruction (such as the comparative method) were developed as a result. PIE is hypothesized to have been spoken as a single language from 4500 BC to 2500 BC during the Late Neolithic to Early Bronze Age, though estimates vary by more than a thousand years. According to the prevailing Kurgan hypothesis, the proto-Indo-European homeland, original homeland of the Proto-Indo-Europeans may have been in the Pontic–Caspian steppe of eastern Europe. The linguistic reconstruction of PIE has provided insight into the pastoral proto-Indo-European culture, culture and patriarchal proto-Indo-European religion, religion of its speakers. As speakers of Proto-Indo-European became isolated from each other through the Indo-European migrations, the regional dialects of Proto-Indo-European spoken by the various groups diverged, as each dialect underwent shifts in pronunciation (the Indo-European sound laws), morphology, and vocabulary. Over many centuries, these dialects transformed into the known ancient Indo-European languages. From there, further linguistic divergence led to the evolution of their current descendants, the modern Indo-European languages. Today, the descendant languages of PIE with the most native speakers are Spanish language, Spanish, English language, English, Portuguese language, Portuguese, Hindustani language, Hindustani (Hindi and Urdu), Bengali language, Bengali, Russian language, Russian, Punjabi language, Punjabi, German language, German, Persian language, Persian, French language, French, Marathi language, Marathi, Italian language, Italian, and Gujarati language, Gujarati. PIE is believed to have had an elaborate system of morphology (linguistics), morphology that included inflection, inflectional suffixes (analogous to English ''life, lives, life's, lives) as well as indo-European ablaut, ablaut (vowel alterations, as preserved in English ''sing, sang, sung, song'') and proto-Indo-European accent, accent. PIE proto-Indo-European nominals, nominals and proto-Indo-European pronouns, pronouns had a complex system of declension, and Proto-Indo-European verbs, verbs similarly had a complex system of Grammatical conjugation, conjugation. The PIE proto-Indo-European phonology, phonology, proto-Indo-European particles, particles, proto-Indo-European numerals, numerals, and indo-European copula, copula are also well-reconstructed. Asterisks are used as a conventional mark of reconstructed words, such as *', *', or *'; these forms are the reconstructed ancestors of the modern English words ''water'', ''wikt:en:hound, hound'', and ''three'', respectively.

Development of the hypothesis

No direct evidence of PIE exists – scholars have reconstructed PIE from its present-day descendants using the comparative method (linguistics), comparative method. For example, compare the pairs of words in Italian and English: and ''foot'', and ''father'', and ''fish''. Since there is a consistent correspondence of the initial consonants that emerges far too frequently to be coincidental, one can assume that these languages stem from a common parent language. Detailed analysis suggests a system of Indo-European sound laws, sound laws to describe the phonetics, phonetic and Phonology, phonological changes from the hypothetical ancestral words to the modern ones. These laws have become so detailed and reliable as to support the Neogrammarian rule: the Indo-European sound laws apply without exception. William Jones (philologist), William Jones, an Anglo-Welsh Philology, philologist and puisne judge in Bengal, caused an academic sensation when he postulated the common ancestry of Sanskrit, Latin, and Greek language, Greek in 1786, but he was not the first to state such a hypothesis. In the 16th century, European visitors to the Indian subcontinent became aware of similarities between Indo-Iranian languages and European languages, and as early as 1653 Marcus Zuerius van Boxhorn had published a proposal for a proto-language ("Scythian") for the following language families: Germanic languages, Germanic, Romance languages, Romance, Hellenic languages, Greek, Baltic languages, Baltic, Slavic languages, Slavic, Celtic languages, Celtic, and Iranian languages, Iranian. In a memoir sent to the in 1767 , a French Jesuit who spent all his life in India, had specifically demonstrated the analogy between Sanskrit and European languages. In the perspective of current academic consensus, Jones's famous work of 1786 was less accurate than his predecessors', as he erroneously included Egyptian language, Egyptian, Japanese language, Japanese and Chinese language, Chinese in the Indo-European languages, while omitting Hindi. In 1818 Rasmus Christian Rask elaborated the set of correspondences to include other Indo-European languages, such as Sanskrit and Greek, and the full range of consonants involved. In 1816 Franz Bopp published ''On the System of Conjugation in Sanskrit'' in which he investigated a common origin of Sanskrit, Persian, Greek, Latin, and German. In 1833 he began publishing the ''Comparative Grammar of Sanskrit, Avestan, Zend, Greek, Latin, Lithuanian, Old Slavic, Gothic, and German''. In 1822 Jacob Grimm formulated what became known as Grimm's law as a general rule in his . Grimm showed correlations between the Germanic and other Indo-European languages and demonstrated that sound change systematically transforms all words of a language. From the 1870s the Neogrammarians proposed that sound laws have no exceptions, as illustrated by Verner's law, published in 1876, which resolved apparent exceptions to Grimm's law by exploring the role of accent (stress) in language change. August Schleicher's ''A Compendium of the Comparative Grammar of the Indo-European, Sanskrit, Greek and Latin Languages'' (1874–77) represented an early attempt to reconstruct the proto-Indo-European language. By the early 1900s Indo-Europeanists had developed well-defined descriptions of PIE which scholars still accept today. Later, the discovery of the Anatolian languages, Anatolian and Tocharian languages added to the corpus of descendant languages. A subtle new principle won wide acceptance: the laryngeal theory which explained irregularities in the reconstruction of Proto-Indo-European phonology as the effects of hypothetical sounds which had disappeared from all documented languages, but which were later observed in newly excavated cuneiform tablets in Anatolian. Julius Pokorny's ('Indo-European Etymological Dictionary', 1959) gave a detailed, though conservative, overview of the lexical knowledge then accumulated. Jerzy Kuryłowicz's 1956 ''Apophonie'' gave a better understanding of Indo-European ablaut. From the 1960s, knowledge of Anatolian became robust enough to establish its relationship to PIE.

Historical and geographical setting

Scholars have proposed multiple hypotheses about when, where, and by whom PIE was spoken. The Kurgan hypothesis, first put forward in 1956 by Marija Gimbutas, has become the most popular. It proposes that the original speakers of PIE were the Yamnaya culture associated with the kurgans (burial mounds) on the Pontic–Caspian steppe north of the Black Sea. According to the theory, they were Eurasian nomads, nomadic pastoralists who domestication of the horse, domesticated the horse, which allowed them to migrate across Europe and Asia in wagons and chariots. By the early 3rd millennium BC, they had expanded throughout the Pontic–Caspian steppe and into eastern Europe. Other theories include the Anatolian hypothesis, the Armenian hypothesis, the Paleolithic Continuity Theory, and the indigenous Aryans theory. An overview map summarises the origin theories.


The table lists the main Indo-European language families. Commonly proposed subgroups of Indo-European languages include Italo-Celtic, Graeco-Aryan, Graeco-Armenian, Graeco-Phrygian, Daco-Thracian, and Thraco-Illyrian. Due to early language contact, there are some lexical similarities between the Proto-Kartvelian language, Proto-Kartvelian and Proto-Indo-European languages.

Marginally attested languages

The Lusitanian language was a marginally attested language spoken in areas near the border between present-day Portugal and Spain. The Venetic language , Venetic and Liburnian language, Liburnian languages known from the North Adriatic region are sometimes classified as Italic. The Paleo-Balkan languages, which occur in or near the Balkan peninsula, do not appear to be members of any of the subfamilies of PIE, but are so poorly attested that proper classification of them is not possible. Albanian and Greek are the only surviving Indo-European descendants of the Paleo-Balkan group. Other major languages of this areal grouping included Phrygian language , Phrygian, Illyrian languages , Illyrian, Thracian language , Thracian, and Dacian language , Dacian.


Proto-Indo-European phonology has been reconstructed in some detail. Notable features of the most widely accepted (but not uncontroversial) reconstruction include: *three series of stop consonants reconstructed as voiceless consonant, voiceless, voiced consonant, voiced, and breathy voiced; *sonorant consonants that could be used syllabic consonant, syllabically; *three so-called laryngeal theory, laryngeal consonants, whose exact pronunciation is not well-established but which are believed to have existed in part based on their detectible effects on adjacent sounds; *the fricative *a vowel system in which and were the most frequently occurring vowels.


The vowels and their commonly used notation are:



The corresponding consonants and their commonly used notation are:


The Proto-Indo-European accent is reconstructed today as having had variable lexical stress, which could appear on any syllable and whose position often varied among different members of a paradigm (e.g. between singular and plural of a verbal paradigm). Stressed syllables received a higher pitch; therefore it is often said that PIE had a Pitch-accent language, pitch accent. The location of the stress is associated with ablaut variations, especially between normal-grade vowels ( and ) and zero-grade (i.e. lack of a vowel), but not entirely predictable from it. The accent is best preserved in Vedic Sanskrit and (in the case of nouns) Ancient Greek, and indirectly attested in a number of phenomena in other IE languages. To account for mismatches between the accent of Vedic Sanskrit and Ancient Greek, as well as a few other phenomena, a few historical linguists prefer to reconstruct PIE as a Tone (linguistics), tone language where each morpheme had an inherent tone; the sequence of tones in a word then evolved, according to that hypothesis, into the placement of lexical stress in different ways in different IE branches.



Proto-Indo-European roots were affix-lacking morphemes which carried the core Lexical (semiotics), lexical meaning of a word and were used to derive related words (cf. the English root "-''friend''-", from which are derived related words such as ''friendship,'' ''friendly'', ''befriend'', and even newly coined words like ''unfriend''). Proto-Indo-European was a fusional language, in which inflectional morphemes signalled the grammatical relationships between words. This dependence on inflectional morphemes means that roots in PIE, unlike those in English, were rarely used without affixes. A root plus a suffix formed a word stem, and a word stem plus a desinence (usually an ending) formed a word.


Many morphemes in Proto-Indo-European had short ''e'' as their inherent vowel; the Indo-European ablaut is the change of this short ''e'' to short ''o'', long ''e'' (ē), long ''o'' (''ō''), or no vowel. This variation in vowels occurred both within inflectional morphology (e.g., different grammatical forms of a noun or verb may have different vowels) and derivational morphology (e.g., a verb and an associated abstract verbal noun may have different vowels). Categories that PIE distinguished through ablaut were often also identifiable by contrasting endings, but the loss of these endings in some later Indo-European languages has led them to use ablaut alone to identify grammatical categories, as in the Modern English words ''sing'', ''sang'', ''sung''.


Proto-Indo-European nominals, Proto-Indo-European nouns are declined for eight or nine cases: *Nominative case, nominative: marks the Subject (grammar), subject of a verb, such as ''They'' in ''They ate''. Words that follow a linking verb and rename the subject of that verb also use the nominative case. Thus, both ''They'' and ''linguists'' are in the nominative case in ''They are linguists''. The nominative is the dictionary form of the noun. *Accusative case, accusative: used for the direct object of a transitive verb. *genitive case, genitive: marks a noun as modifying another noun. *Dative case, dative: used to indicate the indirect object of a transitive verb, such as ''Jacob'' in ''Maria gave Jacob a drink''. *Instrumental case, instrumental: marks the ''instrument'' or means by, or with, which the subject achieves or accomplishes an action. It may be either a physical object or an abstract concept. *ablative case, ablative: used to express motion away from something. *locative case, locative: corresponds vaguely to the English prepositions ''in'', ''on'', ''at'', and ''by''. *Vocative case, vocative: used for a word that identifies an addressee. A vocative expression is one of direct address where the identity of the party spoken to is set forth expressly within a sentence. For example, in the sentence, "I don't know, John", ''John'' is a vocative expression that indicates the party being addressed. *allative case, allative: used as a type of locative case that expresses movement towards something. Only the Anatolian languages use this case, and it may not have existed in Proto-Indo-European at all. Late Proto-Indo-European had three grammatical genders: * masculine, * feminine, * neuter. This system is probably derived from an older, simpler, two-gender system, attested in Anatolian languages: Common gender, common (or Animate gender, animate) and neuter (inanimate) gender. The feminine gender only arose in the later period of the language. All nominals distinguished three Grammatical number, numbers: * singular, * dual, and * plural.


Proto-Indo-European pronouns are difficult to reconstruct, owing to their variety in later languages. PIE had personal pronouns in the first and second grammatical person, but not the third person, where demonstrative pronouns were used instead. The personal pronouns had their own unique forms and endings, and some had Suppletion, two distinct stems; this is most obvious in the first person singular where the two stems are still preserved in English ''I'' and ''me''. There were also two varieties for the accusative, genitive and dative cases, a stressed and an enclitic form.


Proto-Indo-European verbs, like the nouns, exhibited a system of ablaut. The most basic categorisation for the Indo-European verb was grammatical aspect. Verbs were classed as: *stative verb, stative: verbs that depict a state of being *imperfective aspect, imperfective: verbs depicting ongoing, habitual or repeated action *perfective aspect, perfective: verbs depicting a completed action or actions viewed as an entire process. Verbs have at least four grammatical moods: *indicative mood, indicative: indicates that something is a statement of fact; in other words, to express what the speaker considers to be a known state of affairs, as in declarative sentences. *imperative mood, imperative: forms commands or requests, including the giving of prohibition or permission, or any other kind of advice or exhortation. *subjunctive mood, subjunctive: used to express various states of unreality such as wish, emotion, possibility, judgment, opinion, obligation, or action that has not yet occurred *optative mood, optative: indicates a wish or hope. It is similar to the cohortative mood and is closely related to the subjunctive mood. Verbs had two grammatical voices: * active voice, active: used in a clause whose subject expresses the main verb's Agent (grammar), agent. *mediopassive voice, mediopassive: for the middle voice and the passive voice. Verbs had three grammatical persons: first, second and third. Verbs had three grammatical numbers: *singular *dual grammatical number, dual: referring to precisely two of the entities (objects or persons) identified by the noun or pronoun. *plural: a number other than singular or dual. Verbs were also marked by a highly developed system of participles, one for each combination of tense and voice, and an assorted array of verbal nouns and adjectival formations. The following table shows a possible reconstruction of the PIE verb endings from Sihler, which largely represents the current consensus among Indo-Europeanists.


Proto-Indo-European numerals are generally reconstructed as follows: Rather than specifically 100, may originally have meant "a large number".


Proto-Indo-European particles could be used both as adverbs and Preposition and postposition, postpositions, like "under, below". The postpositions became prepositions in most daughter languages. Other reconstructible particles include Affirmative and negative, negators (), Conjunction (grammar), conjunctions ( "and", "or" and others) and an interjection (, an expression of woe or agony).

Derivational morphology

Proto-Indo-European employed various means of deriving words from other words, or directly from verb roots.

Internal derivation

Internal derivation was a process that derived new words through changes in accent and ablaut alone. It was not as productive as external (affixing) derivation, but is firmly established by the evidence of various later languages.

=Possessive adjectives

= Possessive or associated adjectives could be created from nouns through internal derivation. Such words could be used directly as adjectives, or they could be turned back into a noun without any change in morphology, indicating someone or something characterised by the adjective. They could also be used as the second element of a compound. If the first element was a noun, this created an adjective that resembled a present participle in meaning, e.g. "having much rice" or "cutting trees". When turned back into nouns, such compounds were Bahuvrihis or semantically resembled agent nouns. In thematic stems, creating a possessive adjective involved shifting the accent one syllable to the right, for example: * ''*tómh₁-o-s'' "slice" (Greek ''tómos'') > ''*tomh₁-ó-s'' "cutting" (i.e. "making slices"; Greek ''tomós'') > ''*dr-u-tomh₁-ó-s'' "cutting trees" (Greek ''drutómos'' "woodcutter" with irregular accent). * ''*wólh₁-o-s'' "wish" (Sanskrit ''vára-'') > ''*wolh₁-ó-s'' "having wishes" (Sanskrit ''vará-'' "suitor"). In athematic stems, there was a change in the accent/ablaut class. The known four classes followed an ordering, in which a derivation would shift the class one to the right: : acrostatic → proterokinetic → hysterokinetic → amphikinetic The reason for this particular ordering of the classes in derivation is not known. Some examples: * Acrostatic ''*krót-u-s'' ~ ''*krét-u-s'' "strength" (Sanskrit ''krátu-'') > proterokinetic ''*krét-u-s'' ~ ''*kr̥t-éw-s'' "having strength, strong" (Greek ''kratús''). * Hysterokinetic ''*ph₂-tḗr'' ~ ''*ph₂-tr-és'' "father" (Greek ''patḗr'') > amphikinetic ''*h₁su-péh₂-tōr'' ~ ''*h₁su-ph₂-tr-és'' "having a good father" (Greek ''εὑπάτωρ'', eupátōr).


= A vrddhi derivation, named after the Sanskrit grammatical term, signified "of, belonging to, descended from". It was characterised by "upgrading" the root grade, from zero to full (''e'') or from full to lengthened (''ē''). When upgrading from zero to full grade, the vowel could sometimes be inserted in the "wrong" place, creating a different stem from the original full grade. Examples: * full grade ''*swéḱuro-s'' "father-in-law" (Vedic Sanskrit ) > lengthened grade *''swēḱuró-s'' "relating to one's father-in-law" (Vedic , Old High German ''swāgur'' "brother-in-law"). * (''*dyḗw-s'' ~) zero grade ''*diw-és'' "sky" > full grade ''*deyw-o-s'' "god, dyeus, sky god" (Vedic , Latin ''deus'', etc.). Note the difference in vowel placement, ''*dyew-'' in the full-grade stem of the original noun but ''*deyw-'' in the vrddhi derivative.


= Adjectives with accent on the thematic vowel could be turned into nouns by moving the accent back onto the root. A zero grade root could remain so, or be "upgraded" to full grade like in a vrddhi derivative. Some examples: * PIE ''*ǵn̥h₁-tó-s'' "born" (Vedic ''jātá-'') > ''*ǵénh₁-to-'' "thing that is born" (German ''Kind''). * Greek ''leukós'' "white" > ''leũkos'' "a kind of fish", literally "white one". * Vedic ''kṛṣṇá-'' "dark" > ''kṛ́ṣṇa-'' "dark one", also "antelope". This kind of derivation is likely related to the possessive adjectives, and can be seen as essentially the reverse of it.

Affixal derivation


The syntax of the older Indo-European languages has been studied in earnest since at least the late nineteenth century, by such scholars as Hermann Hirt and Berthold Delbrück. In the second half of the twentieth century, interest in the topic increased and led to reconstructions of Proto-Indo-European syntax. Since all the early attested IE languages were inflectional, PIE is thought to have relied primarily on morphological markers, rather than word order, to signal syntax, syntactic relationships within sentences. Still, a default (Markedness, unmarked) word order is thought to have existed in PIE. This was reconstructed by Jacob Wackernagel as being subject–verb–object (SVO), based on evidence in Vedic Sanskrit, and the SVO hypothesis still has some adherents, but the "broad consensus" among PIE scholars is that PIE would have been a subject–object–verb (SOV) language. The SOV default word order with other orders used to express emphasis (e.g., verb–subject–object to emphasise the verb) is attested in Old Indo-Aryan, Old Iranian, Old Latin and Hittite language, Hittite, while traces of it can be found in the enclitic personal pronouns of the Tocharian languages. A shift from OV to VO order is posited to have occurred in late PIE since many of the descendant languages have this order: modern Greek, Romance languages, Romance and Albanian language, Albanian prefer SVO, Insular Celtic has VSO as the default order, and even the Anatolian languages show some signs of this word order shift. The context-dependent order preferences in Baltic, Slavic and Germanic are a complex topic, with some attributing them to outside influences and others to internal developments.

In popular culture

The Ridley Scott film ''Prometheus (2012 film), Prometheus'' features an android named David (played by Michael Fassbender) who learns Proto-Indo-European to communicate with the Engineer, an extraterrestrial whose race may have created humans. David practices PIE by reciting Schleicher's fable. Linguist Dr Anil Biltoo created the film's reconstructed dialogue and had an onscreen role teaching David Schleicher's fable. The 2016 video game ''Far Cry Primal'', set in around 10,000 BC, features dialects of an Fictional language, invented language based partly on PIE, intended to be its fictional predecessor. Linguists constructed three dialects—Wenja, Udam and Izila—one for each of the three featured tribes.

See also

* Indo-European vocabulary * Proto-Indo-European verbs * Proto-Indo-European pronouns * List of Indo-European languages * Indo-European sound laws


Further reading

* * * * * * *

External links

* At the University of Texas Linguistic Research Center
List of online booksIndo-European Lexicon

Proto-Indo-European Lexicon
at the University of Helsinki, Department of Modern Languages, Department of World Cultures, Indo-European Studies *
Indo-European Grammar, Syntax & Etymology Dictionary

Indo-European Lexical Cognacy Database

an online collection of video lectures on Ancient Indo-European languages {{DEFAULTSORT:Proto-Indo-European Language Proto-Indo-European language, Bronze Age Indo-European languages Proto-Indo-Europeans, Language Proto-languages, Indo-European