If there is one Serbian verb you will use in your very first lesson and still reach for years later, it is biti - to be. It holds sentences together the way mortar holds bricks. Lean on it early, trust it often, and the rest of Serbian opens up around it.
Below you will find the present and past tense laid out side by side, with a note on why the past participle changes shape depending on who is speaking. Take your time - this is not a race.
The present tense of BITI
The present forms are short and friendly. You will recognise them almost immediately because they attach themselves to other words like little helpers:
| Person | Serbian | English |
|---|---|---|
| ja | sam | I am |
| ti | si | you are |
| on | je | he is |
| ona | je | she is |
| ono | je | it is |
| mi | smo | we are |
| vi | ste | you are (pl. / formal) |
| oni / one / ona | su | they are |
Notice how the third-person singular is always je regardless of gender - that is one less thing to memorise right now.
The past tense of BITI
The past tense is formed by combining the present of biti with a past participle. That participle - bio, bila, bilo, bili, bile, bila - is the part that changes to reflect who you are talking about. Here is the full picture:
| Person | Serbian | English |
|---|---|---|
| ja (m) | ja sam bio | I was (masc.) |
| ja (f) | ja sam bila | I was (fem.) |
| ti (m) | ti si bio | you were (masc.) |
| ti (f) | ti si bila | you were (fem.) |
| on | on je bio | he was |
| ona | ona je bila | she was |
| ono | ono je bilo | it was |
| mi (masc. / mixed) | mi smo bili | we were |
| mi (all fem.) | mi smo bile | we were (all female) |
| mi (neut. group) | mi smo bila | we were (neut.) |
| vi (masc. / mixed) | vi ste bili | you were (pl.) |
| vi (all fem.) | vi ste bile | you were (all female, pl.) |
| vi (neut.) | vi ste bila | you were (neut., pl.) |
| oni | oni su bili | they were (masc. / mixed) |
| one | one su bile | they were (all female) |
| ona (neut. pl.) | ona su bila | they were (neut.) |
Why agreement matters
The participle (bio / bila / bilo / bili / bile / bila) is not just decoration - it agrees with the gender and number of the subject, which is why Serbian speakers can drop the personal pronoun and still be perfectly understood. That small act of agreement is what makes the language feel precise and alive.
Think of it as Serbian being considerate: it tells you who did the being even when the pronoun is absent, and that will serve you well the moment you start reading real texts.
Practise a tiny pair
Here are two gentle prompts to get the forms off the page and into your mouth:
- Say "Ja sam..." aloud right now - then complete it with something true about yourself (ja sam iz Londona, ja sam student). Do it three times, slow and clear.
- Think of a trip you took last year. If you are a man, say "Mi smo bili u Beogradu." If you are a woman in a group of women, say "Mi smo bile u Beogradu." Notice how natural the switch feels.
Frequently asked questions
Is "sam" both "I am" and part of "I was"?
Yes, and that is one of the beauties of Serbian. In the present, sam stands alone as "I am." In the past, it works as an auxiliary - ja sam bio / bila - teaming up with the participle to say "I was." The little word is doing double duty, and context always makes it clear which meaning is at play.
Do I need the past tense this early in my learning?
You do not need to master it immediately, but it is worth seeing the full picture now. Once you recognise bio and bila in conversation, you will start noticing them everywhere - in songs, news, casual chat - and recognition builds comfort faster than you expect.
Why do masculines and feminines take different endings?
Serbian nouns, pronouns, and adjectives all carry gender, and past participles simply join that system. It can feel like extra work at first, but it is the same logic that runs through the whole language - learn it here with biti and you will recognise it across every verb you ever study.
I am Marina Petrovic, and I have been teaching Serbian online since 2008. My students come from all over the world - what they share is curiosity and patience, and those two things are genuinely all you need. If this post helped you, I am glad; if something confused you, please ask in the comments and I will answer personally.
Ready to go deeper with the verb to be? Visit the full BITI - to be in Serbian hub where you will find audio examples, extended exercises, and notes on the long form (jesam / jesi / jeste).