Tenses & Aspect

Serbian Past Tense (Perfekat): radio sam vs radila sam

Level A2 Tenses & Aspect
Key idea

The perfekat is the everyday past tense you use to say what happened. It's built from two pieces: a short form of biti (sam, si, je, smo, ste, su) plus the l-participle, which you make by dropping -ti from the infinitive. Here's the part that trips up English speakers: the participle agrees with gender and number, so your own gender shows up in the verb. A man says "Radio sam ceo dan," a woman says "Radila sam ceo dan" — same meaning, different ending. Notice too that the little word sam never starts the sentence; it sits in second position. Don't reach for "have" the way English does — Serbian uses biti. Master the agreement and the clitic, and you can talk about yesterday.

Examples

  • Radio sam ceo dan. I worked all day.
  • Ana je kupila hleb. Ana bought bread.
  • Gde ste bili? Where were you?

The full lesson

Everything in the video, in text.

  1. perfekat

    radio sam · radila sam

    Want to tell someone what you did yesterday? You need the perfekat — the everyday past tense. But watch out: the form changes with the speaker's gender. A man says one thing, a woman another. Let's master it for good.

  2. 🕰️

    Perfekat = „sam, si, je…“ + active participle in -o / -la.

    The perfekat is the main past tense of conversation. Without it you can't tell a story or say what happened yesterday. It has two parts: a short form of the verb „to be“ and the so-called active participle — a form ending in the letter L.

  3. biti (enklitika)

    ja sam
    ti si
    on/ona je
    mi smo
    vi ste
    oni su

    The first ingredient is the enclitic of the verb „to be“. „Ja sam, ti si, on je, mi smo, vi ste, oni su.“ The same short, unstressed form you already know — and which never stands at the start of a sentence.

  4. active participle of „raditi“ — gender agreement

    gender
    • masculine (on)
    • feminine (ona)
    • neuter (ono)
    • plural (oni)
    form
    • radio
    • radila
    • radilo
    • radili

    The second ingredient is the active participle. You build it from the infinitive: drop „-ti“ and add an ending for gender. „Raditi“ gives „radio“ for masculine, „radila“ for feminine, „radilo“ for neuter, and „radili“ for plural. The participle agrees with the subject, just like a real adjective.

  5. Radio sam ceo dan.

    male speaker · radio + sam

    Let's put it together. A man talking about himself says — the participle „radio“ plus the enclitic „sam“: Radio sam ceo dan. That means „I worked all day“. Notice that „sam“ comes after the participle, in second position in the sentence.

  6. Radila sam ceo dan.

    female speaker · radila + sam

    Now the same sentence, but a woman is speaking. The participle changes to „radila“. Everything else is the same — only the ending follows the speaker's gender: Radila sam ceo dan. If you're a woman, „radio sam“ sounds wrong — always „radila sam“.

  7. Ana je kupila hleb.

    Ana = feminine → kupila

    Third person. „Ana je kupila hleb.“ The subject is Ana, a woman, so the participle is „kupila“. And the third-person enclitic is „je“: Ana je kupila hleb. If the subject were a man, it would be „kupio“ — „Marko je kupio hleb“.

  8. Gde ste bili?

    plural → bili

    And in the plural? The participle takes the ending „-li“. „Gde ste bili?“ — we're asking several people, so the participle of „to be“ is „bili“: Gde ste bili? Here „ste“ is the enclitic for „vi“, and „bili“ is the plural form.

  9. raditi — perfekat

    ja (m/ž) radio / radila sam
    ti (m/ž) radio / radila si
    on / ona radio / radila je
    mi radili / radile smo
    vi radili / radile ste
    oni / one radili / radile su

    Here's the full picture using the verb „raditi“ across all persons. Remember: the participle shows gender and number, while the enclitic shows person. Two parts, two jobs — and they always go together.

  10. Ja sam radio. (a woman speaking) wrong gender
    Ja sam radila. I worked (female speaker)

    The participle agrees with the speaker's gender — a woman: „radila“.

    Now the most common mistake. A woman who says „ja sam radio“ makes a gender error — the participle has to be „radila“. Your own gender must show up in the past tense.

  11. Ja radio ceo dan. „sam“ is missing
    Radio sam ceo dan. I worked all day.

    The enclitic „sam/si/je…“ is mandatory — don't drop it.

    And the second mistake: dropping the enclitic of „to be“. The participle alone is not a sentence. „Ja radio“ is not correct — it has to be „Ja sam radio“. „Sam“ must not disappear.

  12. the enclitic is always in second position

    starts with the participle
    • Radio sam.
    • Kupila je hleb.
    starts with the subject
    • Ja sam radio.
    • Ana je kupila hleb.

    One more small thing about word order. The enclitic can't go first. If the sentence starts with the participle, you say „Radio sam“. But if it starts with the subject or another word, the enclitic comes right after it — „Ja sam radio“. Always in second position.

  13. Remember

    • perfekat = „sam/si/je…“ + active participle (-o, -la, -lo, -li)
    • the participle agrees with the speaker's gender: radio / radila
    • the enclitic is mandatory and stands in second position

    Let's sum up. The perfekat is the enclitic of „to be“ plus the active participle in L. The participle agrees with gender and number: radio, radila, radilo, radili. Don't drop the enclitic and keep it in second position. Now you can talk about yesterday.