Vocative singular

When you call out to someone — Sir!, Mum!, Marko! — English uses the plain name. Serbian usually changes the ending. Compare Gospodin čeka ("The gentleman is waiting") with Gospodine, čekajte! ("Sir, wait!"): the same noun, but the moment you speak TO the man rather than ABOUT him, gospodin becomes gospodine. This address form is the vocative, the last of the Serbian cases, and it has exactly one job: naming the person (or pet, or thing) you are talking to.

The vocative never has a role in the sentence — it is not the subject, not the object — so it is set off by commas, wherever it stands: Gospodine, izvinite..., Izvinite, gospodine, .... Everything else in the sentence is built as usual.

Masculine nouns

Most masculine nouns ending in a consonant take -e: gospodin → gospodine, doktor → doktore, sin → sine, brat → brate. After a soft consonant (j, lj, nj, ć, đ, č, š, ž) the ending is -u instead: prijatelj → prijatelju, učitelj → učitelju, muž → mužu. Surnames in -ić belong here too: Petrović → Petroviću.

A few very common nouns change their final consonant before -e: čovek → čoveče ("man!", used like "mate!" or "hey!"), Bog → Bože ("God!"). Learn these as words; do not try to build them. And masculine nouns that end in -a — tata, kolega, komšija, deda — simply stay as they are: Tata, dođi!

Feminine nouns

Feminine nouns in -a swap it for -o: gospođa → gospođo, sestra → sestro, majka → majko, baka → bako, duša → dušo ("darling"). Nouns ending in -ica — which includes most female job titles and many endearments — take -e instead: učiteljica → učiteljice, koleginica → koleginice, gospođica → gospođice.

Neuter nouns

Neuter nouns do not change at all: the vocative is the nominative. Dete, gde si? ("Child, where are you?"), Srce moje! ("My heart!"), Zlato! ("Gold!" — a common endearment, roughly "sweetheart").

First names and surnames

Names follow the same endings as ordinary nouns, with one big exception. Male names ending in a consonant take -e: Milan → Milane, Jovan → Jovane, Dragan → Dragane; Petar loses its a: Petre. Male names in -o or -a stay unchanged: Marko, Nikola, Ivo are the same whether you talk about them or to them.

The exception is female names: most of them stay in the nominative — Ana, Jelena, Marija, Milena are addressed exactly as they are written. Only names in -ica take the -ice ending: Milica → Milice, Danica → Danice. Foreign names of either sex are left alone: Džon, Tom, Sara.

With a title, the title takes its vocative and a male surname takes its own: gospodine Petroviću, doktore Jovanoviću. A woman's surname never changes: gospođo Petrović, profesorka Jovanović.

Adjectives and the plural

An adjective in front of a vocative noun uses its ordinary nominative form: dragi prijatelju, draga sestro, poštovani gospodine ("dear sir" — the standard opening of a formal letter or e-mail). In the plural there is nothing new to learn: the vocative plural is identical to the nominative plural (Dragi prijatelji!, Deco! is the one common exception, from the collective deca).

Politeness

In a shop, a café or the street a stranger is gospodine or gospođo (a young woman: gospođice), combined with the polite vi forms: Izvinite, gospodine, koliko je sati?, Izvolite, gospođo. At work and at the doctor's a title is used on its own: Doktore, Profesore, Koleginice. Within the family and among friends the vocative of the relationship word is normal: Mama, Tata, Sine, Bako, Brate (which, like čoveče, also serves as an informal "mate" between young men).

Do not reach for the vocative every time you say a name. It is used when you actually call someone or open a sentence addressed to them; repeating Milane, ... Milane, ... in every sentence of a conversation sounds odd, just as repeating someone's name does in English. And when a name has no vocative form — Ana, Marko, Nikola, any foreign name — do not invent one: the nominative is correct.