The perfect: clitic biti plus the l-participle

So far everything you have said happened now. To say what happened yesterday, Serbian does not invent a new set of verb endings. It puts two words side by side: the little form of biti you learned long ago — sam, si, je, smo, ste, su — and a special past form of the main verb.

Radim. — I work. Radio sam. — I worked. The sam says who. The radio says what happened — and, as you will see, it says something about who as well.

Part one: the little biti

This is the clitic present of biti, unchanged from lesson four. It carries the person, exactly as it does in Ja sam student.

Part two: the l-participle

The second word is built from the infinitive: drop the -ti and add an ending. That ending agrees with the subject in gender and number — the way an adjective agrees with its noun.

The masculine singular is the odd one: the ending is -o, not -lo. The l turned into o centuries ago, so radil became radio, gledal became gledao. Everything else keeps the l you can hear.

This means a man and a woman say the same sentence differently. Bio sam u bioskopu. — I was at the cinema, said by a man. Bila sam u bioskopu. — the same, said by a woman. Nobody can say it neutrally, so decide who is speaking before you open your mouth.

Dropping the agreement is the classic mistake. If the subject is sestra, the participle must be feminine — Sestra je radila, never Sestra je radio.

Three plurals, not one

In the plural Serbian still keeps the three genders apart. Men and boys — or any mixed group — take -li. A group that is all female takes -le. Neuter plural nouns, and deca, take -la.

• Bratovi drugovi su pevali. — my brother's friends sang.
• Moje sestre su pevale. — my sisters sang.
• Deca su pevala. — the children sang.

The neuter plural -la looks exactly like the feminine singular -la. Nothing distinguishes them but the subject, so read the subject first: Ona je spavala is one woman, Deca su spavala is a roomful of children.

Where the words go

sam, si, je, smo, ste, su are clitics, so the rule you met with ga and mi applies here too: they never open a sentence. They stand after the first stressed word.

• Radio sam ceo dan. — the participle opens, the clitic follows.
• Ja sam radio ceo dan. — the pronoun opens, the clitic follows.
• Juče sam radio ceo dan. — the time word opens, the clitic follows.

With a noun subject the clitic slips in after it: Ana je kuvala. — never Je Ana kuvala. For a question, put da li in front of the whole thing: Da li je Ana kuvala?