Breakdown of Voitko arvata, onko kysymys vaikea?
olla
to be
vaikea
difficult / hard
voida
can, to be able to
kysymys
question
Questions & Answers about Voitko arvata, onko kysymys vaikea?
Why is there a "-ko" at the end of both Voitko and onko?
This sentence actually contains two questions! The first -ko is in Voitko (Can you) to make the main sentence a direct yes/no question. The second is in onko (is it) to form the indirect question. When English uses "if" or "whether" for an indirect question, Finnish attaches the -ko/-kö ending to the verb instead.
Could I use the word jos (if) to say "if the question is difficult"?
No, you cannot. In Finnish, jos is only used for conditions (like "If it rains, I will stay home"). When "if" means "whether" in an indirect question (like "Can you guess whether..."), you must use the -ko/-kö ending. Here, it is attached to on (is) to make onko.
Why is there a comma before onko?
In Finnish punctuation rules, you almost always separate clauses with a comma. The first part (Can you guess) and the second part (if the question is difficult) both have their own verbs, so they are separate clauses. Therefore, a comma is required after arvata.
Why does the verb arvata (to guess) stay in its dictionary form here?
The first verb in the sentence is voida (can / to be able to). When you use an auxiliary verb like voida, the main action verb that comes after it must stay in its basic dictionary form (the first infinitive). Because voit already shows who is doing the action, arvata does not need to change.