The i-declension of feminine nouns

At A1 you learned that a noun ending in a consonant is usually masculine. That is true most of the time — but Serbian has a large group of feminine nouns that end in a consonant, and many of them are among the most common words in the language: stvar (thing), noć (night), ljubav (love), reč (word), smrt (death), pomoć (help), and almost every noun ending in -ost: radost (joy), mladost (youth), mogućnost (possibility).

You can see they are feminine from the words around them: velika radost, ova stvar, moja ljubav, duga noć. Adjectives, demonstratives and possessives take exactly the same feminine endings you already know — nothing new there. What is new is the noun itself: it has its own set of endings, and it is a very simple one.

One ending does almost everything: -i

Add -i to the consonant and you have the genitive, dative and locative singular, and the whole plural apart from the dative-locative-instrumental. Only two cases stand out: the accusative singular (no ending at all) and the dative, locative and instrumental plural (-ima, like the masculines).

• Ljubav je važna stvar. — Love is an important thing. (nominative)
• Ne razumem tu reč. — I don't understand that word. (accusative)
• Bez ljubavi nema sreće. — There is no happiness without love. (genitive)
• U mladosti je mnogo putovao. — He travelled a lot in his youth. (locative)
• Uvek radi s ljubavlju. — She always works with love. (instrumental)
• Ove stvari nisu moje. — These things are not mine. (nominative plural)
• Već šest noći ne spavam dobro. — I haven't been sleeping well for six nights now. (genitive plural after a number)
• Često mislimo o tim stvarima. — We often think about those things. (locative plural)

The accusative looks like the nominative

This is the big difference from feminine nouns in -a. With žena the object changes: Vidim ženu. With an i-declension noun the object does not change: Vidim stvar, Osećam radost, Verujem u ljubav. The adjective in front still takes its normal feminine accusative ending, so the change is carried by the adjective alone: Osećam veliku radost.

Do not add -u to these nouns. Osećam radost, never radostu. If the noun ends in a consonant and is feminine, the accusative singular is the bare word, while its adjective says -u: ovu stvar, tu reč, veliku ljubav.

The instrumental: two endings, both correct

In the instrumental singular you may simply use -i, like the other cases: Šta da radim s ovom stvari? That is always correct. You will also hear -ju, especially in set expressions of feeling: s ljubavlju (with love), s radošću (with joy). When -ju is added, the consonant before it often changes (ljubav → ljubavlju, radost → radošću), which is why the -i form is easier to start with. Learn s ljubavlju and s radošću as they are, and use -i for everything else.

noću looks like an instrumental of noć, but it is used as an adverb meaning at night (you met it with the bare time expressions). For "with the night" and in phrases with an adjective, use noći.

Many -i forms look alike — let the context decide

stvari can be genitive singular, dative-locative singular, plural nominative, accusative or genitive. You tell them apart from the preposition, the verb, the number word and above all the adjective or demonstrative: ove stvari (these things, plural), ove stvari in bez ove stvari (genitive singular), toj stvari (dative-locative singular), ovih stvari (genitive plural).

A few of these nouns lose an a before the ending: misao (thought) → misli, mislima. The endings themselves are the same.