Nominals in the Proto-Indo-European language (PIE) include nouns, adjectives and pronouns. Their morphology and semantics have been reconstructed by modern linguists based on similarities found across all Indo-European languages. This article discusses nouns and adjectives, while Proto-Indo-European pronouns are treated elsewhere.
- 1 Introduction
- 2 Morphology
- 3 Grammatical categories
- 4 Athematic accent/ablaut classes
- 5 Heteroclitic stems
- 6 Adjectives
- 7 Examples
- 8 Derivation
- 9 Notes
- 10 References
The following table shows some example declensions of Proto-Indo-European (PIE) nouns, based on the reconstruction of Ringe (2006).
|acrostatic root noun||hysterokinetic r-stem||proterokinetic ti-stem||proterokinetic neuter u-stem||eh₂-stem (ā-stem)||o-stem||neuter o-stem|
|gloss||night (f.)||father (m.)||thought (f.)||tree (n.)||grain (f.)||nest (m.)||work (n.)|
1Because of the large number of laryngeal consonants in this noun class, possible "Post-PIE" (non-Anatolian) forms are shown, after the loss of laryngeals. In reality, not all daughter languages developed in the same fashion. However, all but the Anatolian languages (e.g. Hittite) eventually lost the laryngeal consonants, and the developments were fairly similar across languages; as a result, the forms given are largely accurate. The caron underneath vowels that were adjacent to laryngeals (e.g. *ō̬) is meant to indicate that in some languages (particularly the Balto-Slavic languages), these vowels maintained some property that distinguished them from non-laryngeal vowels. 2The ending was underlyingly *-éh₂, but laryngeals were deleted before a pause, leaving in this case a laryngeal-colored vowel [á].
These tables demonstrate some of the most important properties of PIE nouns:
- There were eight cases and three genders.
- There were multiple declensions, distinguished both by the form of the stem added to the root (*-r-, *-n-, *-s-, *-u/w-, *-i/y-, *-eh₂-, etc.) and the position of the accent: acrostatic ("stationary on the root"), proterokinetic ("mobile, towards the front"), hysterokinetic ("mobile, towards the back"), amphikinetic ("mobile, towards both sides"). The last three accent classes were are mobile, in that the accent could move around from one form to another within a paradigm.
- There were two large categories of declensions, athematic (with consonantal stems) and thematic (with a vocalic stem *-o/e-).
- There were different sets of endings in use. The largest difference is between the endings of athematic and thematic nouns, but neuter nouns also had separate endings in the merged nominative/vocative/accusative case.
- There was a complex system of ablaut (variation in vowel quality, between *e, *o, *ē, *ō and no vowel). This potentially occurred in all three of the root, stem and ending. The actual ablaut forms used depended on the stem class and accent class and were correlated with the position of the accent.
There were strong pressures early on to eliminate some of the complexities of this system, especially the ablaut variations in the root. For example, the ablaut variant *nékʷt- of *nókʷts "night" is found only in Hittite; evidently, root ablaut in this word was eliminated in favor of uniform *nókʷt- already in the proto-language, after the separation of the Anatolian languages. In the case of *méntis "thought", no daughter languages have root ablaut in this word, but some generalized the strong variant *ment- and some the weak variant *mn̥t- (cf. Gothic ana-minds "supposition" < *mentís vs. ga-munds "remembrance" < *mn̥tís).
The basic morphological structure of Proto-Indo-European (PIE) nouns and adjectives is the same as that of PIE verbs. A lexical word (as would appear in a dictionary) is formed by adding a suffix (S) onto a root (R) to form a stem. The word is then inflected by adding an ending (E) to a stem. The root indicates a basic concept (e.g. *deh₃- "give"), while the stem carries a more specific meaning based on the combination of root and suffix (e. g. *déh₃-tor- "giver", *déh₃-o- "gift"). The ending carries grammatical information, including case, number, and gender. (The gender is an inherent property of a noun but is part of the inflection of an adjective, because it must agree with the gender of the noun it modifies.)
Thus, the general morphological form of such words is R+S+E.
The process of forming a lexical stem from a root is known in general as derivational morphology, while the process of inflecting that stem is known as inflectional morphology. As elsewhere, the possible suffixes that can be added to a given root, and the meaning that results, are not entirely predictable, while the process of inflection is largely predictable in both form and meaning.
Extensive ablaut (vowel variation, between e, o, ē, ō and no vowel) occurred in PIE, in both derivation and inflection and in the root, suffix, and ending. Variation in the position of the PIE accent likewise occurs in both derivation and inflection, and is often considered part of the system of ablaut. Originally, ablaut variations in all three of root, suffix and ending occurred between different inflections within a given paradigm. For example, the nominative form *léimons "lake" (composed of root léi-, suffix -mon- and ending -s) co-occurred with the genitive form *limnés (composed of root li-, suffix -mn- and ending -és). In this case, the nominative has the ablaut vowels é–o-Ø while the genitive has the ablaut vowels Ø–Ø-é — i.e. all three components have different ablaut vowels, and the stress position has likewise moved. A large number of different patterns of ablaut variation existed; language learners had to both learn the ablaut patterns and memorize which pattern went with which word. There was a certain regularity of which patterns occurred with which suffixes and formations, but with many exceptions.
Already by late PIE times, this system was extensively simplified, and daughter languages show a steady trend towards more and more regularization and simplification. Note that far more simplification occurred in the late PIE nominal system than in the verbal system, where the original PIE ablaut variations were maintained essentially intact well into the recorded history of conservative daughter languages such as Sanskrit and Ancient Greek, as well as in the Germanic languages (in the form of strong verbs).
As with PIE verbs, a basic distinction is made between primary formations, i.e. words formed directly from a root as described above, and secondary formations, which are formed from existing words (whether primary or secondary).
Athematic and thematic nominals
A fundamental distinction is made between thematic and athematic nominals. Thematic nominals have a stem ending in a thematic vowel, *-o- in almost all cases, sometimes ablauting to *-e-. The accent is fixed on the same syllable throughout the inflection. The stem of athematic nominals ends in a consonant. They have a complex system of accent and ablaut alterations between the root, the stem and the ending (see below). This type is generally held as more archaic.
From the perspective of the daughter languages, a distinction is often made between vowel stems (i-, u-, (y)ā-, (y)o-stems) and consonantic stems (the rest). However, from the PIE perspective, only the o-stems are truly vocalic. Both *i and *u are vocalic allophones of underlying consonants (the glides *y and *w, respectively), and post-PIE *ā was actually *eh₂ in PIE. Nonetheless, it still makes sense to distinguish the individual stems. Although at an earlier stage, all athematic stems may have been inflected alike, by late PIE times each stem had its own inflectional peculiarities.
Among the most common athematic stems are root stems, i-stems, u-stems, eh₂-stems, n-stems, nt-stems, r-stems and s-stems. Within each of these, numerous subclasses developed by late PIE times.
Originally, -h₂ by itself was a suffix used to form feminine nouns (originally, perhaps these were collective nouns). Remnants of this period exist in (e.g.) the eh₂-stems, ih₂-stems, uh₂-stems and bare h₂-stems, which were originally the feminine equivalents of the o-stems, i-stems, u-stems and root nouns, respectively. Already by late PIE times, however, this system was breaking down. -eh₂ became generalized as the feminine suffix, and eh₂-stem nouns evolved more and more in the direction of thematic o-stems, with fixed ablaut and accent, increasingly idiosyncratic endings and frequent borrowing of endings from the o-stems. Nonetheless, clear traces of the earlier system are seen especially in Sanskrit, where the reflexes of ih₂-stems and uh₂-stems (ī-stems and ū-stems, respectively) still exist as distinct classes comprising largely feminine nouns. (Over time, these stem classes merged with i-stems and u-stems, with frequent crossover of endings.)
PIE also had a class of monosyllabic athematic or so-called root nouns which lack a derivational suffix (or equivalently, have a zero suffix), the ending being directly added to the root (as in *dóm-s, derived from *dem- "build"). These nouns can also be interpreted as having a zero suffix or one without a phonetic body (*dóm-Ø-s).
Prefixes and reduplication
Some nominals were formed with prefixes. An example is *ni-sd-os "nest", derived from the verb *sed- "sit" by adding a local prefix and thus meaning "where [the bird] sits" or the like.
A special kind of prefixation, called reduplication, uses the first part of the root plus a vowel as a prefix. For example, *kʷel(h₁)- "turn" gives *kʷe-kʷl(h₁)-os "wheel". This type of derivation is also found in verbs, mainly to form the perfect.
PIE nouns, as well as adjectives and pronouns, are subject to the system of PIE nominal inflection, inflecting for eight or nine cases: nominative, accusative, vocative, genitive, dative, instrumental, ablative, locative, and possibly a directive or allative. The so-called strong or direct cases are the nominative and the vocative for all numbers, and the accusative case for singular and dual (and possibly plural as well), and the rest are the weak or oblique cases. This classification is relevant for inflecting the athematic nominals of different accent classes (see below).
Three numbers were distinguished: singular, dual and plural. Many (possibly all) athematic neuter nouns had a special collective form instead of the plural, which inflected with singular endings, but with the ending -h2 in the direct cases, and an amphikinetic ablaut pattern (see below).
Late PIE had three genders: masculine, feminine and neuter. Originally, there probably were only an animate (masculine/feminine) and an inanimate (neuter) gender. This view is supported by the existence of certain classes of Latin and Ancient Greek adjectives which inflect only for two sets of endings, one for masculine and feminine, the other for neuter. Further evidence comes from the Anatolian languages which exhibit only the animate and the inanimate gender. However, this could also mean that Proto-Anatolian inherited a three-gender PIE system, and subsequently Hittite and other Old Anatolian languages eliminated the feminine by merging it with the masculine. The typically feminine ā-stems are considered to originate from the same form as the neuter plural, originally an abstract/collective derivational suffix *-h₂.
Not all authors reconstruct the same sets of endings. Some endings are difficult to reconstruct. For example, the original form of the genitive plural is a particular thorny issue, because different daughter languages appear to reflect different proto-forms. It is variously reconstructed as *-ōm, *-om, *-oHom, etc. Meanwhile, the dual endings of cases other than the merged nominative/vocative/accusative are often considered impossible to reconstruct because these endings are attested sparsely and diverge radically in different languages.
The following shows three modern mainstream reconstructions. Sihler (1995) remains closest to the data, often reconstructing multiple forms when daughter languages show divergent outcomes. Ringe (2006) is somewhat more speculative, willing to assume analogical changes in some cases to explain divergent outcomes from a single source form. Fortson (2004) is between Sihler and Ringe.
The thematic vowel *-o- ablauts to *-e- only in word-final position in the vocative singular, and before *h₂ in the neuter nominative and accusative plural. The vocative singular is also the only case for which the thematic nouns show accent retraction, a leftward shift of the accent, denoted by *-ĕ.
|Singular||Nominative||*-s ~ *-Ø||*-s||*-o-s|
|Instrumental||*-bhi ~ *-mi ~ *-(e)h₁||*-é-h₁ ~ *-h₁||*-h₁||*-o-h₁ ~ *-e-h₁||*-o-h₁ > *-ō|
|Dative||*-ey||*-ōy||*-o-ey > *-ōy|
|Ablative||*-s ~ *-os ~ *-es||*-s||*-ōt, *-āt||*-o-ad||*-o(h₂)at > *-ōt|
|Genitive||*-ī, *-osyo||*-o-syo (?)||*-o-s (?)|
|Locative||*-i, *-Ø§||*-o-y ~ *-e-y||(**-e →) *-e-y||*-o-y|
|Dual||Nom./Voc./Acc.||*-h₁e ~ *-h₁||*-h₁e||*-h₁||*-o-h₁ ~ *-o-(h₁)e||*-o-h₁ > *-ō|
|Gen./Loc.||???||*-ows (?)||???||*-eyows ~ *-oyows (?)||???||???|
|*-o-es > *-ōs|
|Nom./Voc./Acc. Neuter||*-h₂||*-h₂ ~ *-Ø||*-h₂||*-e-h₂ > *-ā|
|Instrumental||*-bhis ~ *-mis ~ *-mīs||*-bhí||*-bh-†||*-ōys ~ *-o-mis (?) ~ *-o-mīs (?)||*-ōys||*-o(i)bh-†|
|Dat./Abl.||*-bhos ~ -mos||*-mos||*-o-bhos ~ o-mos||*-o-mos (*-o-y-mos?)|
†The dative, instrumental and ablative plural endings probably contained a *bʰ but are of uncertain structure otherwise. They might also have been of post-PIE date.
§For athematic nouns, an endingless locative is reconstructed in addition to the ordinary locative singular in *-i. In contrast to the other weak cases, it typically has full or lengthened grade of the stem.
A much more speculative reconstruction is found in Beekes (1995). This reconstruction does not give separate tables for the thematic and athematic endings, assuming that they were originally the same and only differentiated in daughter languages. In general, this reconstruction assumes much more analogical change than most other current reconstructions of the same endings.
|Nominative||*-s, *-Ø||*-m, *-Ø||*-h₁(e)||*-ih₁||*-es||*-h₂, *-Ø|
Athematic accent/ablaut classes
Early PIE nouns showed complex patterns of ablaut, where the root, stem and ending all showed ablaut variations. Polysyllabic athematic nominals (type R+S+E) exhibit four characteristic patterns that include accent and ablaut alternations throughout the paradigm between the root, the stem and the ending. Root nouns (type R+E) show similar behaviour, but with only two patterns. A distinction can be made between "kinetic" types (Ancient Greek kinetikos = moving) and "static" types (Ancient Greek statikos = holding still).
|acrostatic (or acrodynamic)
(akros = beginning)
|Normal||strong||ó||Ø||Ø||nom. sg. *nókʷ-t-s||"night"|
|weak||é||Ø||Ø||gen. sg. *nékʷ-t-s|
|strong||ḗ||Ø||Ø||nom. sg. *mḗh₁-n̥s||"moon"|
|weak||é||Ø||Ø||gen. sg. *méh₁-n̥s-os|
|proterokinetic (or proterodynamic)
(proteros = before)
|Normal||strong||é||Ø||Ø||nom. sg. *mén-ti-s||"thought"|
|weak||Ø||é||Ø||gen. sg. *mn̥-téy-s|
|Old acrostatic||strong||ó||Ø||Ø||nom. sg. *dór-u||"tree"|
|weak||Ø||é||Ø||gen. sg. *dr-éw-s|
|hysterokinetic (or hysterodynamic)
(hysteros = later)
|strong||Ø||é||Ø||nom. sg. *ph₂-tḗr < *ph₂-tér-s||"father"|
|weak||Ø||Ø||é||gen. sg. *ph₂-tr-és|
|loc. sg.||Ø||é||Ø||loc. sg. *ph₂-tér-(i)|
|amphikinetic (or amphidynamic)
(amphis = on both sides)
|strong||é||o||Ø||nom. sg. *léy-mō < *léy-mon-s||"lake"|
|weak||Ø||Ø||é||gen. sg. *li-mn-és|
|loc. sg.||Ø||é||Ø||loc. sg. *li-mén-(i)|
|acrostatic||Normal||strong||ó||Ø||nom. sg. *dṓm < *dóm-s||"house"|
|weak||é||Ø||gen. sg. *dém-s|
|strong||ḗ||Ø||nom. sg. *mḗms||"meat"|
|weak||é||Ø||gen. sg. *méms-os?|
|amphikinetic (?)||strong||é||Ø||nom. sg. *wréh₂d-s||"root"|
|weak||Ø||é||gen. sg. *wr̥h₂d-és|
|loc. sg.||é||Ø||loc. sg. *wréh₂d-(i)|
- In the strong cases of proterokinetic nominals, the accent is placed on the penultimate syllable of the stem. When there is only one suffix, the root will be the penultimate syllable; when there is more than one suffix, the penultimate syllable will be a suffix, and the root will appear unaccented and in the zero grade.
- There is an unexpected o-grade of the suffix in the strong cases of polysyllabic amphikinetic nominals. Another unusual property of this class is the locative singular having a stressed e-grade suffix.
The classification of the amphikinetic root nouns is disputed. Since these words have no suffix, they differ from the amphikinetic polysyllables in the strong cases (no o-grade) and in the locative singular (no e-grade suffix). Some scholars prefer to call these nouns amphikinetic and the corresponding polysyllables holokinetic (or holodynamic, from holos = whole).
Some also list mesostatic (meso = middle) and teleutostatic types, with the accent fixed on the suffix and the ending, respectively, but their existence in PIE is disputed. The classes can then be grouped into three static (acrostatic, mesostatic, teleutostatic) and three or four mobile (proterokinetic, hysterokinetic, amphikinetic, holokinetic) paradigms.
By late PIE, the above system was already significantly eroded, with one of the root ablaut grades tending to be extended throughout the paradigm. Erosion is much more extensive in all the daughter languages, with only the oldest stages of most languages showing any root ablaut, and typically only in a small number of irregular nouns. Examples are:
- Vedic Sanskrit dā́ru "wood", gen. drṓs < PIE *dóru, *dreus
- Old Irish ben "woman", gen. mná < PIE *gʷén-eH₂, *gʷn-eH₂-s
- Old Avestan zyā̊ "winter", gen. zimō < PIE *ǵhyems, *ǵhimós
- Ancient Greek Zdeús "Zeus", gen. Di(w)ós, Vedic Sanskrit d(i)yāúḥ "heaven", gen. diváḥ, dyōḥ, both < PIE *dyēus, *déiwos "sky, day, god"
- Proto-Germanic reconstructed *tan(þ)s "tooth" gen. *tundiz < PIE *h₃dónts, h₃dn̥tés, with the nominative stem preserved in Old Norse tǫnn, Old Saxon tand, Old English tōþ, and the genitive stem in Gothic tundus.
The most extensive remains are in Vedic Sanskrit and Old Avestan (the oldest recorded stages of oldest Indic and Iranian languages, c. 1300-1700 BC); younger stages of the same languages already show extensive regularization.
In many cases, a former ablauting paradigm was generalized in the daughter languages, but in different ways. For example, Ancient Greek dóru "spear" < PIE nominative *dóru "wood, tree" and Old English trēo "tree" < PIE genitive dreu-s reflect different stems of a PIE ablauting paradigm PIE *dóru, *dreus, PIE nominative *dóru and genitive *dreu-s, which is still reflected directly in Vedic Sanskrit nom. dā́ru "wood", gen. drṓs. We can similarly reconstruct PIE *ǵónu, ǵnéus "knee" from Ancient Greek gónu and Old English knēo. In this case we don't have an extant ablauting paradigm in a single language, although we have Avestan accusative žnūm and Modern Persian zānū, which strongly implies that Proto-Iranian had an ablauting paradigm (and quite possibly Avestan also; we can't tell because the nominative is not extant). We can also clearly reconstruct an ablauting paradigm *pōds, *ped- "foot" based on Greek pous gen. podós (< *pō(d)s, *pod-) vs. Latin pēs gen. pedis (< *ped-) vs. Old English fōt (< *pōd-), with differing ablaut grades among cognate forms in different languages.
In some cases we would expect ablaut based on the form (given numerous other examples of ablauting nouns of the same form), but a single ablaut variant is found throughout the paradigm. In such cases it is often assumed that the noun did show ablaut in early PIE, but was generalized to a single form already in late PIE or shortly afterwards. An example is Greek génus "chin, jaw", Sanskrit hánus "jaw", Latin gena "cheek", Gothic kinnus "cheek". All except the Latin form suggest a masculine u-stem with non-ablauting PIE root *ǵen-, but certain irregularities (the position of the accent, the unexpected feminine ā-stem form in Latin, the unexpected Gothic stem kinn- < ǵenw-, the ablaut found in Greek gnáthos "jaw" < PIE *ǵnH₂dh-, Lithuanian žándas "jawbone" < *ǵonHdh-os) suggest an original ablauting neuter noun *ǵénu, *ǵnéus in early PIE, generalizing the nominative ablaut already in late PIE and switching to the masculine u-stem in the post-PIE period. Another example is *nokʷts "night", where an acrostatic root paradigm might be expected based on the form, but the consistent stem *nokʷt- is found throughout the family. With the discovery of Hittite, however, the form /nekʷts/ "in the evening" was found, evidently a genitive and indicating that early PIE did indeed have an acrostatic paradigm, smoothed out already in late PIE but still incomplete at the time of the separation of Hittite.
Some athematic noun stems have different final consonants in different cases; these are termed heteroclitic stems. Most of these stems end in *-r- in the nominative and accusative singular, and in *-n- in the other cases. Examples of such r/n-stems include the acrostatic neuter *wód-r̥ "water", genitive *wéd-n-s; and *peh₂-wr̥ "fire", genitive *ph₂-wen-s or similar.
A possible l/n-stem is *seh₂-wōl "sun", genitive *sh₂-wén-s or the like.
Adjectives in PIE generally have the same form as the corresponding nouns, although when paradigms are gender-specific more than one paradigm may be combined to form an adjectival paradigm, which must be declined for gender as well as number and case. The paradigmatic example of this is o/ā-stem adjectives, which have masculine forms following masculine o-stems (-os), feminine forms following ā-stems and neuter forms following neuter o-stems (-om). u-stem, i-stem, and n-stem adjectives use the corresponding neuter noun variants for their neuter forms, and the normal masculine/feminine noun variants for both masculine and feminine.
A number of adjectival roots form part of the Caland system. The cognates derived from these roots in different daughter languages often do not agree in formation, but show certain characteristic properties:
- Adjectives are formed using zero-ablaut ro-stems, u-stems or nt-stems
- Adjectives are sometimes formed using i-stems, especially in the first part of a compound
- Corresponding stative verbs in -eh₁ often exist
1. *h₁le(n)gʷh- "light (in weight)":
- ro-stems: Ancient Greek elaphrós "light, quick"; Old High German lungar "fast"
- u-stems: Ancient Greek elakhús "small"; Sanskrit laghú-, raghú- "quick, light, small"; Avestan ragu- "fast"; Latin levis "light" < *h₁legʷh-us; Lithuanian lengvùs "light"; Old Church Slavonic lŭgŭkŭ "light"'
- i-stems: Avestan rǝnjišta- "fastest"
2. *h₂erǵ- "white":
- ro-stems: Ancient Greek argós < *argrós "white"; Sanskrit ṛjrá- "brilliant"
- u-stems: Tocharian B ārkwi "white"
- i-stems: Ancient Greek argi-kéraunos "with bright lightning"
3. *h₁reudh- "red":
- ro-stems: Ancient Greek eruthrós "red"; Latin ruber "red"; Tocharian B ratre "red"
- i-stems: Sanskrit rudhiras (mixed with ro-stem)
- -eh₁ verbs: Latin rubēo "be red", Old High German rōtēn "shine red"
4. *bherǵh- "high"
- ro-stems: Tocharian B pärkare "high"
- u-stems: Hittite parku- "high"; Armenian barjr "high" < *-u-
- i-stems: Avestan bǝrǝzi- "high" in compounds
- nt-stems: Sanskrit brḥánt- "high", Avestan bǝrǝzant- "high", Germanic name Burgund-, Irish name Brigit, Tocharian A koṃ-pärkānt "sunrise"
5. *dheub- "deep"
- ro-stems: Tocharian B tapre "high" < *dhub-ro-
- u-stems: Lithuanian dubùs "hollow"
The following are example declensions of a number of different types of nouns, based on the reconstruction of Ringe (2006).
|acrostatic root noun||acrostatic lengthened root noun||amphikinetic (?) root noun||hysterokinetic r-stem||amphikinetic n-stem||hysterokinetic n-stem|
|gloss||night (f.)||moon (m.)||foot (m.)||father (m.)||lake (m.)||bull (m.) (< "ox")|
|proterokinetic neuter r/n-stem||amphikinetic collective neuter r/n-stem||amphikinetic m-stem||proterokinetic ti-stem||proterokinetic tu-stem||proterokinetic neuter u-stem|
|gloss||water (n.)||water(s) (n.)||earth (f.)||thought (f.)||taste (m.)||tree (n.)|
|neuter s-stem||proterokinetic h₂-stem||hysterokinetic h₂-stem||eh₂-stem (ā-stem)||o-stem||neuter o-stem|
|gloss||cloud (n.)||woman (f.) (> "queen")||tongue (f.)||grain (f.)||nest (m.)||work (n.)|
|acc.||*nébʰos||*gʷénh₂m̥||*dn̥ǵʰwéh₂m (-ām)||*dʰoHnéh₂m (-ā́m)||*nisdóm||*wérǵom|
|acc.||*nébʰōs||*gʷénh₂n̥s||*dn̥ǵʰwéh₂ns (-ās)||*dʰoHnéh₂ns (-ās)||*nisdóns||*wérǵeh₂|
New words are formed in several ways, namely:
- by ablaut alternations (the root consonantism is intact, but vocalization changes), e.g. *ḱernes "horned" from *ḱernos "horn, roe". Many PIE adjectives formed this way were subsequently nominalized in daughter languages.
- by alternating accent (i.e. switching to another accent/ablaut class), e.g. *bʰóros "burden", but *bʰorós "carrier"
- by derivational suffixes (possibly coupled with changes 1 and 2)
- by reduplication
- by combining lexical morphemes themselves (compounding); e.g. PIE *drḱ-h₂ḱru "tear", literally "eye-bitter"
- Ringe (2006:47–50)
- Words like *mén-ti-s are athematic because the *i is just the vocalic form of the glide *y, the full grade of the suffix being *-tey-. See Proto-Indo-European phonology: Vowels for further information on the syllabification rules for PIE sonorants.
- *dem- "build" is also reconstructed as *demh₂- which could mean that "house" is actually *dómh₂-s.
- Fortson (2004:102)
- Ringe (2006)
- Fortson (2004:103)
- Mallory, J. P. and D. Q. Adams. 2006. The Oxford introduction to Proto-Indo-European and the Proto-Indo-European world. P.59
- Google Books: The Ancient Languages of Asia Minor
- Luraghi, Silvia. 2009. The origin of the feminine gender in PIE. An old problem in a new perspective. In Bubenik, V., J. Hewson and S. Rose (ed.)Grammatical change in Indo-European languages.
- Sihler (1995:248)
- Ringe (2006:41)
- Fortson (2004:113)
- Beekes (1995:[page needed])
- Fortson (2004:108–109)
- Don Ringe (2006). From Proto-Indo-European to Proto-Germanic. Oxford University Press. p. 47. ISBN 978-0-19-955229-0.
- Benjamin W. Fortson (2004). Indo-European Language and Culture: An Introduction. Blackwell Publishing. p. 108. ISBN 1-4051-0316-7.
- Actually, only *ph₂tḗr and *dṓm can be reconstructed, but these forms could have developed from the regular ones (*ph₂térs and *dóms, respectively) via Szemerényi's law.
- Ringe (2006:45)
- Fortson (2004:109ff)
- Meier-Brügger, Fritz & Mayrhofer (2003:216)
- Meier-Brügger, Fritz & Mayrhofer (2003, F 315)
- Fortson (2004:107)
- Ringe (2006:280)
- Fortson (2004:110–111)
- John J. Lowe, Caland Adjectives and Participles in Sanskrit and Proto-Indo-European. .
- Beekes, Robert S. P. (1995). Comparative Indo-European Linguistics. Amsterdam: John Benjamins. ISBN 90-272-2150-2 (Europe), ISBN 1-55619-504-4 (U.S.).
- Buck, Carl Darling (1933). Comparative Grammar of Greek and Latin. University of Chicago Press. ISBN 0-226-07931-7.
- Fortson, Benjamin W., IV (2004). Indo-European Language and Culture. Blackwell Publishing. ISBN 1-4051-0316-7.
- Meier-Brügger, Michael; Fritz, Matthias; Mayrhofer, Manfred (2003). Indo-European Linguistics. Berlin; New York: Walter de Gruyter. ISBN 3-11-017433-2.
- Ringe, Don (2006). From Proto-Indo-European to Proto-Germanic. Oxford University Press. ISBN 978-0-19-955229-0.
- Sihler, Andrew L. (1995). New Comparative Grammar of Greek and Latin. Oxford University Press. ISBN 0-19-508345-8.
- Whitney, William Dwight (1889). Sanskrit Grammar. Harvard University Press. ISBN 0-486-43136-3.