Mobile Past Endings

1. Common Hosts and Forms:
• 2nd Person Singular (-ś): Very common in everyday speech (Gdzieś był? / Coś ty zrobił?).
• 1st/2nd Person Plural (-śmy, -ście): Established in Polish, with frequency and stylistic effect varying by speaker and region (Myśmy to zrobili.).
• 1st Person Singular (-m): While attaching it to the pronoun ja is archaic (Jam to zrobił), it survives in everyday expressive or colloquial speech attached to conjunctions or question words (Alem się zmęczył!).
• 3rd Person (Zero Ending): This pattern only applies to the 1st and 2nd person. The 3rd person past tense has a 'zero' person ending, meaning there are no mobile endings to detach for 'he', 'she', 'it', or 'they' (e.g., on był, oni byli).

2. Spelling and Pronunciation:
If the host word ends in a consonant, an extra -e- is often inserted to make it pronounceable (e.g., jak + ś = jakeś). The neutral alternative always remains the inflected verb: Jak to zrobiłeś?. Detached combinations differ in familiarity and register; do not manufacture them from every possible host.

3. The "że" Controversy:
It is perfectly correct to attach these endings to the conjunction że (that), e.g., Wiem, żeście tam byli (I know that you were there). However, using że as a meaningless "dummy" word just to hold the ending at the start of a sentence (e.g., Żeśmy poszli instead of Poszliśmy or Myśmy poszli) is considered a colloquial error by normative grammars.

4. A Common Myth:
Many native speakers mistakenly believe that detached endings are sloppy or incorrect. In reality, linguists emphasize that mobile clitics are a traditional feature of Polish, with the acceptability and register of individual host combinations considered separately. Attaching them to question words (like Gdzieś był?) is a standard, neutral feature of spoken Polish, while pronoun hosts such as myśmy are also established. Neither detached nor verb-attached endings measure education or competence.

5. Conditional Mood:
The exact same mobile pattern applies to the conditional mood endings (-bym, -byś, -byśmy, -byście), which combine the conditional particle by with these exact same mobile past endings (-m, -ś, -śmy, -ście). For example, you can say Co zrobiłbyś? or Co byś zrobił?

6. Ambiguity with Indefinite Pronouns:
Attaching -ś to question words creates forms that look and sound identical to indefinite pronouns (e.g., gdzieś = somewhere, coś = something). In sentences like Coś ty zrobił?, coś means co + ś (what + you), not "something".

7. Preposition Restriction:
Mobile endings cannot attach to bare prepositions. For example, *Wśmy kinie byli is incorrect. An older or expressive pattern can attach them within the following phrase (W kinieśmy byli); ordinary contemporary prose can simply retain Byliśmy w kinie.

Conditional placement does not mean identical spelling: Co byś zrobił? has separate byś. Under the spelling rules effective in 2026, by with its person ending is written separately from ordinary conjunctions, while established words such as gdyby remain joined.