Masculine declension   •   Neuter declension   •   Feminine declension   •   Athematic declension   •   Irregular nouns   •   The vocative

Like most Slavic languages, nouns in Interslavic have three grammatical genders (masculine, feminine, neuter), two numbers (singular, plural) and six cases (nominative, accusative, genitive, dative, instrumental, locative). Some Slavic languages also have a vocative, which can also be used in Interslavic, if desired. Because the vocative is not a real case, it will be treated separately. It is possible to use Interslavic without grammatical cases, the way Bulgarian and Macedonian do. In that case, their function is taken over by prepositions or word order.

Long and complicated paradigms are to be avoided, but we cannot escape distinguishing between a few different word classes.

These are the basic endings. The forms between brackets are used after soft stems (in most cases, this is a matter of applying the o/e and y/i rules):
Nom -o (-e) -a
Acc -Ø / -a 1
Gen -a -y (-e) -i
Dat -u -ě (-i) -i
Ins -om (-em) -ojų (-ejų)2 -jų
Loc -ě (-i, -u) -ě (-i) -i
Nom -y (-i) -a -y (-e) -i
Acc -y (-i) / ov (-ev) 1
Gen -ov (-ev) -ij
Dat -am -jam
Ins -ami -jami
Loc -ah -jah

1 When a masculine noun is inanimate, the accusative has the same form as the nominative; when it is animate, the genitive is used instead.
2 In words with the ending -ija, it deserves recommendation to shorten the ending to : s Sŕbijų instead of s Sŕbijejų.

Below follow a few examples of each declension:

Masculine declension

Virtually all masculine nouns end in a consonant. Basically, there is only one declensional pattern for masculine nouns, but a few things need to be remembered:

Five examples: pes „dog”, dom „house”, mųž „man”, kraj „country”, język „language”.

hard, animate hard, inanimate soft, animate soft, inanimate velar
Nom pes dom mųž kraj język
Acc psa dom mųža kraj język
Gen psa doma mųža kraja języka
Dat psu domu mųžu kraju języku
Ins psom domom mųžem krajem językom
Loc psě domě mųži kraji języku
Nom psy domy mųži kraji języki
Acc psov domy mųžev kraji języki
Gen psov domov mųžev krajev językov
Dat psam domam mųžam krajam językam
Ins psami domami mųžami krajami językami
Loc psah domah mųžah krajah językah

Neuter declension

Neuter nouns end in -o or -e. Except for the nominative/accusative and the genitive plural, their inflection is identical to the masculine declension. Please note:

There is also special group of neuter nouns with the ending , for example imę „name” (stem: imen-) and telę „calf” (stem: telęt-). It also includes a few words on -o, for example nebo „heaven” (stem: nebes-). In Old Church Slavonic they belonged to a special declension, which nowadays has vanished in most languages. They can be inflected as ordinary neuter nouns (as if their nominatives were imeno and teleto), they can also be declined according to the more archaic athematic declension.

Because we usually do not distinguish between ę and e, it is useful to remember that the noun ending in -e is always neuter, and as a rule of thumb, when this -e is preceded by:

For the rest, declension is always regular. Two examples: slovo „word”, morje „sea”

hard soft
Nom slovo morje
Acc slovo morje
Gen slova morja
Dat slovu morju
Ins slovom morjem
Loc slově morji
Nom slova morja
Acc slova morja
Gen slov morj
Dat slovam morjam
Ins slovami morjami
Loc slovah morjah

Feminine declension

Most feminine nouns are characterised by the ending -a. Again, we distinguish between hard and soft stems. In the case of feminine nouns the differences between hard and soft declension are not merely a matter of applying the o/e rule. As a rule, the endings -y and -ě after a hard consonant become -e and -i after a soft consonant (in other words, they are „reversed”). A few words on -i belong to this group as well (for example boginji, which is inflected as if the nominative singular were *boginja). The -a declension also includes a few masculine nouns with the ending -a referring to male persons, like sluga „servant” and sųdja „judge”. The latter follow the masculine pattern in the plural.

A second group are feminine nouns ending in a consonant, most of which carry the ending -osť.

Examples: žena „woman”, zemja „earth”, kosť „bone”.

hard soft
Nom žena zemja kosť
Acc ženų zemjų kosť
Gen ženy zemje kosti
Dat ženě zemji kosti
Ins ženojų zemjejų kostjų
Loc ženě zemji kosti
Nom ženy zemje kosti
Acc ženy zemje kosti
Gen žen zem(ej) kostij
Dat ženam zemjam kostjam
Ins ženami zemjami kostjami
Loc ženah zemjah kostjah

Athematic declension

Except for the regular declensions listed above, Old Church Slavonic also had another declension type, the so-called athematic declension. Nouns of this type have gone various ways in the modern Slavic languages, mostly merging them into one or more of the regular declension types. Interslavic projects choose various approaches to this group, but some of them preserve it.

This declension type includes nouns of all three genders, but most numerous among them are neuter nouns. The following subtypes can be distinguished:

m. (-en-) n. (-men-) n. (-ęt-) n. (-es-) f. (-v-) f. (-r-)
Nom kameń imę telę nebo cŕkòv mati
Acc kameń imę telę nebo cŕkòv mati
Gen kamene imene telęte nebese cŕkve matere
Dat kameni imeni telęti nebesi cŕkvi materi
Ins kamenem imenem telętem nebesem cŕkòvjų materjų
Loc kameni imeni telęti nebesi cŕkvi materi
Nom kameni imena telęta nebesa cŕkvi materi
Acc kameni imena telęta nebesa cŕkvi materi
Gen kamenev imen telęt nebes cŕkvij materij
Dat kamenam imenam telętam nebesam cŕkvam materam
Ins kamenami imenami telętami nebesami cŕkvami materami
Loc kamenah imenah telętah nebesah cŕkvah materah

It is possible to avoid the entire athematic declension and inflect these words according to the regular declensions. In that case:

Irregular nouns

Although we have done our very best to avoid irregularity, in a few cases it cannot be avoided without defying naturalism. The following nouns have an irregular plural (in all four cases declined as a feminine noun of the kost type):

Regular plurals (člověki, oka etc.) can be used as well, but some of them sound very strange to the Slavic ear, even though they will be understood anyway.

The vocative

Apart from the six regular cases, some Slavic languages also have a vocative, used for addressing a person or object directly. Although it is often listed as one, the vocative is not a real case, and it behaves significantly different from other cases: it does not have a plural, it never affects neuter nouns, adjectives or pronouns, and it has nothing to do with the syntactic structure of the sentence.

Several Slavic languages have no vocative at all or preserved only some fossilised remnants of it. This goes for Russian, Belarussian, Slovak, Lower Sorbian, Slovene and Polabian. Some other languages do have vocatives, but show an increasing tendency towards replacing it with the nominative (Cashubian, Macedonian, Bulgarian). In Upper Sorbian the vocative is used only for masculine words. The only languages where the vocative is really in full use are Ukrainian, Polish, Czech and Serbo-Croatian.

For this reason, the nominative can always be used instead of the vocative. However, if you prefer to use a real vocative anyway, then the following forms are recommended: