Past Stem Changes

Level 3

While most verbs form the past tense by dropping '-ć', two groups change their stems: verbs ending in '-nąć' (which often lose the 'ną') and verbs ending in '-ść', '-źć', or '-c' (which restore their original stem consonant).

How It Works

In Polish, the past tense is usually predictable, but two specific classes of verbs undergo stem changes:

1. The Loss of -ną-
Verbs ending in -nąć that describe a change of state (inchoative verbs) usually drop the -ną- entirely before adding the past tense marker -ł-, provided the root ends in a consonant. For example, zmarznąć (to freeze) becomes zmarzł (he froze), not *zmarznął. Note that in casual speech, many Poles do retain the -ną-, but dropping it is the standard literary form.

2. Consonant Restoration (-ść, -źć, -c)
Verbs ending in -ść, -źć, or -c hide their original stem consonant in the infinitive. When forming the past tense, this consonant 'reappears' because the past tense marker -ł- doesn't trigger the same sound shifts as the infinitive ending. To find the correct stem, look at the 1st person singular present tense:

  • -ść / -źć: Usually restores d, t, s, or z. (e.g., nieść → stem nies- → niósł)
  • -c: Usually restores k or g. (e.g., móc → stem mog- → mógł)

These changes are frequently accompanied by vowel alternations, such as e changing to o or o changing to ó.

Examples (5)

  1. Kwiat w wazonie szybko zwiędł.

    The flower in the vase withered quickly.

    Word by Word: Flower in vase quickly withered.

    The infinitive is 'zwiędnąć'. Because it describes a change of state, the '-ną-' is dropped in the past tense.

  2. On nie mógł przyjść na spotkanie.

    He could not come to the meeting.

    Word by Word: He not could come on meeting.

    The infinitive is 'móc'. The 'c' restores to the stem consonant 'g' in the past tense.

  3. Dziewczynka niosła ciężki plecak.

    The girl was carrying a heavy backpack.

    Word by Word: Girl carried heavy backpack.

    The infinitive is 'nieść'. The 'ś' restores to the stem consonant 's' in the past tense.

  4. Zupa już wystygła.

    The soup has already cooled down.

    Word by Word: Soup already cooled-down.

    From 'wystygnąć'. The '-ną-' is dropped in the feminine past tense form.

  5. Mój brat upiekł pyszne ciasto.

    My brother baked a delicious cake.

    Word by Word: My brother baked delicious cake.

    From 'upiec'. The 'c' restores to the stem consonant 'k' in the past tense.

Common Mistakes

  • Retaining '-ną-' in verbs that should drop it.

    On zmarznął na przystanku.
    On zmarzł na przystanku.

    Both forms exist, but zmarzł is the standard past form of 'zmarznąć'. The longer zmarznął is rare. Drop the -ną- in this past form.

  • Forgetting the vowel alternation in the masculine form.

    On nie mogł tego zrobić.
    On nie mógł tego zrobić.

    When 'g' is restored in 'móc', the 'o' often changes to 'ó' in the masculine singular past tense.

How It Connects

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Past Stem ChangesLevel 3

Learn This First

Learn Past Tense, Three Noun Genders before Past Stem Changes.