Breakdown of Eikö ole totta, että juhla oli eilen?
olla
to be
ei
no / not (en, et, ei, emme, ette, eivät)
eilen
yesterday
että
that (conjunction)
Questions & Answers about Eikö ole totta, että juhla oli eilen?
How does the word eikö work in this sentence?
Eikö is the negative verb ei (meaning "it does not" or "is not") with the question ending -kö attached. To ask a negative question like "Isn't it?", Finnish attaches the question particle directly to the negative verb.
Why does the sentence use ole instead of on?
Because of the negative verb ei. Just like in a normal negative sentence (ei ole meaning "is not"), the main verb must drop to its special negative form (ole). Adding the question ending to make eikö ole doesn't change this rule.
Why is the word for "true" written as totta instead of its basic form tosi?
When expressing general statements or abstract ideas like "it is true", Finnish uses the partitive form of the adjective. You will see this same pattern in phrases like on tärkeää (it is important) or on vaikeaa (it is difficult).
Can I leave out the word että like we often drop "that" in English?
No, you usually cannot skip että in Finnish. While an English speaker might say "Isn't it true the party was yesterday?", Finnish requires että to properly link the two parts of the sentence.