4.1.1. Declension is made by adding terminations to different stem endings, vowel or consonant. The various phonetic changes in the language have given rise to the different declensions. Most of the case-endings, as shown in this Modern Indo-European grammar, contain also the final letter of the stem.

Adjectives are generally declined like nouns, and are etymologically to be classed with them, but they have some peculiarities of inflection which will be later explained.

4.1.2. Nouns and adjectives are inflected in four regular Declensions, distinguished by their final phonemes – characteristic of the Stem –, and by the opposition of different forms in irregular nouns. They are numbered following Graeco-Latin tradition: First or a-Declension, Second or o-Declension, Third or i/u-Declension, Fourth or Consonant Declension, and the variable nouns.

NOTE. The Second or o-Declension is also the Thematic Declension, opposed to the rest – and probably older in the evolution of PIE nominal inflection –, which form together the Athematic Declension.

The Stem of a noun may be found, if a consonant stem, by omitting the case-ending; if a vowel stem, by substituting for the case-ending the characteristic vowel.

NOTE. Most Indo-Europeanists tend to distinguish at least two major types of declension for the oldest PIE, Thematic and Athematic. Thematic nominal stems are formed with a suffix -o- (in vocative -e), and the stem does not undergo ablaut. The Athematic stems are more archaic, and they are classified further by their ablaut behaviour: acro-dynamic, protero-dynamic, hystero-dynamic and holo-dynamic, after the positioning of the early PIE accent in the paradigm. For more on this, see Beekes (1995) and Meier-Brügger (2003).

4.1.3. The following are General Rules of Declension:

a. The Nominative singular for animates ends in -s when the stem endings are i, u, ī, ū, Diphthong, Occlusive and Thematic (-os), or -Ø in ā, Sonant and s; while in the plural -es is general, -s for those in ā, and -os for the Thematic ones.

b. The Accusative singular of all masculines and feminines ends in -m or -ṃ (after consonant), the Accusative plural in -ns or -ṇs.

c. The Vocative singular for animates is always -Ø, and in the plural it is identical to the Nominative.

d. The Genitive singular is common to animates and inanimates, it is formed with -s: -s, -es, -os. A very old alternative possibility is extended -os-jo. The Genitive plural is formed in -ōm, and in -ām in a-stems.

e. The Obliques singular end usually in -i: it can be -i, -ei, -ēi, -oi, -ōi or -āi, and their extensions. In the plural, there are two series of declensions, Instr. -bhis/-mis (from Sg. -bhi), Dat.-Abl. -bhos/-mos (PII -bhjas) as well as (BSl. and PII) Loc. in -su, Gk. -si.

NOTE. Meier-Brügger (2003) considers that “[e]vidence seems to indicate that while the dative and ablative plural were marked with *-mos, the instrumental plural was marked with *-b^hi” in PIH, and similarly Mallory & Adams (2006) differentiate for the oldest PIE declension a Dat. -mus, instrumental -bhi, and Abl. -bh(j)os. Comparison shows an Ins. Sg. -bhi, (cf. Gk. -p^hi, Myc -pi, and also Arm. Ins. marb), BSl. -mi (cf. Lith. akmenimì, O.C.S. kamenĭmĭ) and for North-West IE dialects a division between Italic+Celtic and Germanic+Balto-Slavic Plural forms: Celtic shows traces of an Instrumental -bhis (cf. O.Ir. Dat.-Loc.-Inst.-Abl. cridib, and in Graeco-Aryan O.Ind. sūnúbhis, Av. bāzubīs, Arm. srtiwkh), Italic and Celtic show a Dat.-Abl. -bhos (cf. Celtiberian Dat.-Loc.-Inst.-Abl. arecoraticubos, Lat. matribus, Osc. luisarifs), while Balto-Slavic shows Inst. -mis (cf. Lith. sunumìs, O.C.S. synumĭ), Dat.-Abl. -mos (cf. O.C.S. synŭmŭ, Lith. sūnùms, sūnùmus), and Germanic shows a Dat.-Abl.-Inst. -m-. Also, Indo-Iranian -bhjas (<*-bhjos), according to Meier-Brügger, “can thus be regarded as a cross between the instrumental *-b^hi  and the dative/ablative *-mos”. Even if some might consider these data enough to draw conclusions about a well-differentiated common PIH plural declension system, we think it is more appropriate to maintain in MIE the (conservative) reconstructible North-West IE West/East dialectal differentiation, i.e. Dat.-Abl. -bhos/-mos (PII -bhjas), and Instr. -bhis/-mis, without using any of those assimilation theories proposed, as e.g. PIE Inst. *-m- → dialectal *-bh-.

f. Inanimates have a syncretic form for Nom.-Ac.-Voc. -Ø in Athematic, or -m in Thematic. The plural forms end in -ā in thematics and -a in athematics.

NOTE. About the nominative/accusative neuter plural, Meier-Brügger states: “in terms of content, the idea of a collective mass is certainly dominant. Therefore, the collective suffix (= athematic *-h₂- and thematic *-e-h₂-) is used, no ending (zero) added (…) The understanding of the neuter plural as collective explains the ancient IE characteristic, observable in isolated cases, of combination of the neuter plural and the singular of a verb (…)”.

g. All Animates have the same form in the plural for Nom.-Voc., in -es.

4.1.4. The so-called Oblique cases – opposed to the Straight ones, Nom.-Acc.-Voc –, are Genitive and the Obliques proper, i.e. Dative, Locative, Instrumental and Ablative. IE languages show an irregular Oblique declension system.

NOTE. Sanskrit or Avestan had 8 cases, Anatolian and Italic dialects show up to 8 (cf. Osc. Loc. aasai for Lat. ‘in ārā’, or Ins. cadeis amnud for Lat. ‘inimicitiae causae’, preiuatud for Lat. ‘prīuātō’, etc.), while Latin shows six and a semisystematic Locative notion; Balto-Slavic shows seven, Mycenaean at least six cases, while Koiné Greek and Proto-Germanic had five.

Nominal Desinences (Summary)

1. They are usually Animate nouns and end in ā (or jā), and rarely in ja/ī, ē, and ō.  Those in ā are very common, generally feminine in nouns and always in adjectives, and they are used to make feminines in the adjectival Motion. Those in ja/ī are rare, generally feminine, and etymologically identical to the Neuter plural in Nom.-Acc.-Voc. Those in ō and ē are feminine only in lesser used words.

NOTE. The entire stem could have been reduced to MIE a (hence a-Declension), because this is the origin of the whole PIE stem system in PIH, the ending *-(e)h₂. See §3.7.3.

2. MIE First Declension corresponds loosely to the Latin First Declension (cf. Lat. rosa, rosae, or puella, puellae), and to the Ancient Greek Alpha Declension (cf. Gk. χώρᾱ, χώρᾱς, or τῑμή, τῑμῆς).

a-Declension Paradigm

NOTE. This declension in ā, older *-eh₂, is usually reconstructed in the Singular as from older PIH Nom.-Vocc. *-eh₂, Acc. *-eh₂m, Gen.(-Abl.) *-eh₂os, Dat. *-eh₂ei, Loc. *-eh₂i, Ins. *-eh₂eh₁ or *-eh₂bhi, Abl. *-eh₂ed; as, Dat. *h₁ekweh₂ei → ekwāi.

3. It is therefore identical to those nouns in r, n, s of the Fourth Declension, but for some details in vocalism: the Gen. has an -s and not -es/-os; the difference between Nom. and Voc. is that of -ā and -a. The zero-grade of the Nom.-Acc.-Voc. in ja/ī stems is different from the Gen. in -jā.

1. Nominative Singular in -Ø; as, ekwā, mare, deiwā, goddess, patrjā, fatherland, adj. cowij, bovine.

Examples of ja/ī include potnja/potnī, lady, mistress, djewja/djewī, (sky) goddess.

NOTE. Even though ja/ī was known to Late PIE speakers, those are rarely seen in North-West IE, and consequently they are usually MIE -jā; as, MIE potnjā.

Those in ē, ō, also rare, make the Nominative in -s; as, bhidhēs, from Lat. fides (but cf. O.Lat. fidis), trust, spekjēs, species, etc.

2. Accusative Singular in -m; as, ekwām, patrjām, potnjam/potnīm, spekjēm.

3. Vocative Singular in -Ø. It is normally identical to the Nominative, but disambiguation could happen with distinct vowel grades, i.e. Nom. in -ā, Voc. in -a.

4. Genitive Singular in -s; as, ekwās, patrjās, spekjēs.

The theme in ja/ī produces a Genitive Singular in -ās; as, potnjās.

5. Dative-Ablative Singular in -āi, ekwāi, patrjāi.

NOTE. It comes probably from an older PIE general Dat. *-ei ending; as, *h₁ekweh₂-ei → ekwāi.

There is also a form -ei for themes in ē and in ja/ī.

6. Locative in -āi; as, ekwāi, patrjāi.

7. Instrumental in -Ø, -ā-bhi/-ā-mi; as, ékwābhi, pátrjāmi.

 

1. The following table presents the plural paradigm of the a-Declension.

NOTE. The Plural is reconstructed as from PIH Nom.-Vocc. *-eh₂s, Acc. *-eh₂ns (<*-eh₂-m-s), Gen.(-Abl.) *-eh₂om, Dat.-Abl. *-eh₂bh(j)os, Loc. *-eh₂su, Ins. *-eh₂bhis; as, *h₁ekweh₂es → ekwās.

2. The Nominative-Vocative Plural in -s: ekwās, patrjās, cowijs.

3. The Accusative Plural in -ms: ekwāns, patrjāns.

4. The Genitive Plural in -m: ekwām, patrjām.

5. The Dative and Ablative Plural in -bhos, -mos, and -bhjos; as, ékwābhos, ékwāmos.

6. The Locative Plural in -su (also PGk -si); as, ékwāsu, pátrjāsu.

6. The Instrumental Plural in -bhis, -mis; as, ékwābhis, ékwāmis.

NOTE. The Obliques have also special forms Gk. -āisi, -ais, Lat. -ais; as, Lat. rosīs<*rosais.

1.  The Stem of nouns of the Second Declension ends in e/o, and they are usually called Thematic. They can be animates and inanimates, as well as adjectives. The inanimates have an ending -m only in Nom.-Acc.-Voc. The animates, with a Nominative in -s, are generally masculine in nouns and adjectives, but there are also feminine nouns and animate adjectives in -os, probably remains of the old indistinctness of declension.

NOTE. The o-Declension is probably very recent in PIE – even though it happened already in PIH, before the Proto-Anatolian split – and that’s why it is homogeneous in most IE dialects. As Mallory & Adams (2006) say, “[t]he o-stems were the most productive form of declension. By this is meant that through time, especially at the end of the Proto-Indo-European period and into the early histories of the individual Indo-European languages, the o-stems appeared to proliferate and replace other stem types. In Vedic Sanskrit, for example, they constitute more than half of all nouns. High productivity is often interpreted as evidence that the o-stems are a later declensional form than many of the other stems. Highly productive forms are ultimately capable of replacing many other forms as they provide the most active model by which speakers might decline a form”.

2. MIE Second Declension is equivalent to the Second Declension in Latin (cf. Lat. dominus, dominī, or uinum, uinī), and to the Omicron Declension in Greek (cf. Gk. λόγος, λόγου, or δῶρον, δῶρου).

o-Declension Paradigm

 

NOTE 1. This model could have been written without the initial vowel -o-, because the probable origin of this vowel is the ending vowel of some thematic stems, while other, primitive athematic stems were reinterpreted, and an -o- was added to their stems by way of analogy. So, this paradigm could be read Nom. -s, Acc. -m, Gen. -s, -sjo, -so, and so on.

NOTE 2. The thematic declension is usually reconstructed in the Singular as from older PIH Nom. *-os, Voc. *-e, Acc. *-om (neu. Nom.-Voc.-Acc. *-om), Gen. *-os, Dat. *-ōi (<*-o-ei), Loc. *-oi, Ins. *-oh₁, Abl. *-ōd (<-o-ed); as, Dat. *wl̥k^wo-ei → wḷqōi, Abl. *wl̥k^wo-ed → wḷqōd.

1. Nominative Singular Animate in -os; as in wḷqos, wolf, dómūnos, lord, wīrós, man, adj. cīwós, alive.

2. Accusative Singular Animate in -om; as in wḷqom, dómūnom, cīwóm.

3. Vocative Singular Animate in -e; as in wḷqe, dómūne, cīwé.

5. The Nom.-Acc.-Voc. Sg. Inanimate in -om; as in jugóm, yoke, adj. newom, new.

4. Genitive Singular in -os, -osjo, also -e/oso, -ī; as in wḷqosjo, jugós, dómūnī.

NOTE. The original Genitive form -os is rare, as the Genitive had to be distinguished from the Nominative. This disambiguation happens by alternatively lengthening the ending, as -os-jo (or e/os-o) or changing it altogether, as in -ī.

6. Dative Singular in -ōi: wḷqōi, dómūnōi, newōi, jugṓi.

7. Locative Singular in -oi: wḷqoi, dómūnoi, newoi, jugói.

8. Instrumental Singular in -ō: wḷqō, dómūnō, newō, jugṓ.

9. The Ablative Singular is formed in -ōd: wḷqōd, cīwṓd, jugṓd.

1. The Thematic Plural system is usually depicted as follows:

NOTE. The Animate Plural is reconstructed as PIH Nom.-Voc. *-ōs (<*-o-es), Acc. *-ons (<*-o-m-s), Gen.(-Abl.) *-m (<*-o-om), Dat.-Abl. *-o(i)bh(j)os/-omos, Loc. *-oisu (<*-o-eis-su), Ins. *-is (<*-o-eis); as,*wl̥kwo-es → wḷqōs. Inanimates have a Nom.-Voc.-Acc in *-oh₂ (or *-eh₂) evolved as -ā in most dialects. A Nom.-Voc. (pronominal) ending -oi is also found.

2. The Nominative-Vocative Animate Plural in -ōs; as, wḷqōs, dómūnōs, wīrṓs.

3. The Accusative Animate Plural in -ons; as, wḷqons, dómūnons, cīwóns.

4. The Nom.-Voc.-Acc. Inanimate Plural usually in -ā; as, jug, cīw.

5. The Genitive Plural in -ōm; as, wḷqōm, dómūnōm, cīwṓm, jugṓm.

6. For the Obliques Plural, Dat.-Abl. wḷqomos, Loc. wīrṓisu, Ins. jugṓis.

1. Third Declension nouns end in i, u (also ī, ū) and Diphthong.

2. This declension usually corresponds to Latin nouns of the Third Declension in -i (cf. Lat. ciuis, ciuis, or pars, partis), and of the Fourth Declension in -u (cf. Lat. cornū, cornūs, or portus, portūs).

i/u-Declension Paradigm

NOTE 1. The so-called common, basic or athematic paradigm, the hypothetically oldest attainable PIE noun declension system, is reconstructed in the Singular as Nom. *-Ø, *-s, Acc. *-m, Voc. *-Ø, Gen.(-Abl.) *-(é/o)s, Dat. *-ei, Loc. *-Ø, *-i, Ins. *-(é)h₁, Abl. *-(e)d. This was a paradigm common to the i/u and Consonant declension (v.i.), and it was probably inherited (and innovated) by the first and second declensions.

NOTE 2. Reduplication or combination with the alternating endings -i, -ei/-oi and -u, -eu/-ou, was a common resort in the attested dialects that distinguished Dat. and Loc. in this declension, as in -i-ei, -ei-ei, -eu-ei, and so on, to differentiate similar forms.

3. The animates in i and u are masculine or feminine (indifferent to the distinction in adjectives); those in ī and ū, always feminine.

4. The -s can indicate Nominative and Genitive: the distinction is made through the full-grade of the vowel before the declension, i.e. Type I (older) Gen. -ei-s (or oi-s) for i, -eu-s (or ou-s) for u; Type II (newer) in -(e)i-os, -(e)u-os.

NOTE. The Vocative of the animates is the same as the Nom.-Acc.-Voc. of the inanimates.

1. Nominative Singular Animate in -s; as in owis, sheep, noqtis, night, ghostis, guest, sūnús, son, egnis, fire, pṛtus, ford, swḗdhus, custom; adj. swādus, pleasant.

2. Accusative Singular Animate in -m; as in owim, noqtim, ghostim, sūnúm.

3. Vocative Singular Animate in -Ø, or full -ei, -eu; owi, sūnéu/sūneu, swēdhu.

NOTE. Full vocalism helps differentiate animates (in -ei, -eu) from inanimates (in -i, -u).

4. The Nom.-Acc.-Voc. Singular Inanimate in -Ø; as in mari, sea, kṛdi, heart, peku, cattle, deru, wood, medhu, mead, adj. swādu.

5. Type I Genitive Singular in -eis, -eus, also -ois, -ous; as, ghosteis, mareis, sūnéus, swēdheus, adj. swādeus.

Type II in -(e)jos, -(e)wos; as, owjos, noqtjos, kṛdejós, swḗdhewos, pékewos.

NOTE. Some -ei-, -eu- genitives were remade into the newer -(e)jo-, -(e)wo-; as, old dreus, pṛtéus, owéis, egnéis, pekéus, into MIE dérewos, pṛtwos, owjos, egnjos, pékewos.

6. Dat. Sg. in -ei, usually full -ei-ei, -eu-ei; as, ghóstejei, pékewei.

NOTE. For a Dat. Sg. in -ei, pure stem or full ending plus -i, cf. Gk. -seï (<*-t-ej-i?), O.C.S. kosti.

7. Loc. Sg. in -ei, -eu, usually lengthened -ēi, -ēu, -ewi; as, noqtēi, sunḗu.

8. Ins. -ī, -ū (<*-h₁), in -ē (<*-eh₁) following the Gen., or -bhi/-mi: pṛtū, pṛtwē.

NOTE. The Obliques show weak stems (root ablaut and accent shift) in old root nouns, v.i.

Its inflection is similar to the consonant stems, and they have no alternating vowels before the declension; ī and ū are substituted before vowel by -ij, -uw. They are always feminine, and they cannot be inanimates nor adjectives. They are mostly PIE roots (in *-iH, *-uH), and found mainly in Indo-Iranian.

 

1. There are long diphthongs āu, ēu, ōu, ēi, which sometimes present short vowels.

NOTE. Other endings that follow this declension, as ā, ē, ō are probably remains of older diphthongs. Therefore, these can all be classified as Diphthong endings, because the original stems were formed as diphthongs in the language history.

In zero grade Genitives there are forms with -i- or -ij- or -u- or -uw-, depending on the diphthongs.

NOTE 1.  Some secondary formations – especially found in Greek – are so declined, in -eus, -euos as in Av. bāzāus, Arm.,Gk. Basileus, possibly from PIE -āus (Perpillou, 1973) but Beekes (2007) considers it Pre-Greek.

NOTE 2. Stang’s law governs the word-final sequences of a vowel + semivowel j or w +  nasal, simplified in PIE so that semivowels are dropped, with compensatory lengthening of a preceding vowel, i.e. VwM,VjM → VːM; as, djēm, not *djewm̥; cōm, not *g^wowm̥, cōns, not *g^wown̥s, etc. A similar trend is found with laryngeals, *Vh₂m > VːM; as, sūm, also attested as suwṃ, etc.

1. The following table depicts the general plural system, common to the Fourth Declension.