Learn Finnish: En tiedä, onko palkinto tällä kierroksella. - I do not know if the prize is in this round.

In Finnish, jos is only used for a conditional "if" (like "If it rains..."). When "if" really means "whether" in an indirect question (like "I don't know if..."), you cannot use jos. Instead, you attach the question clitic -ko or -kö to the word being questioned. Here, it attaches to on (is) to make onko (whether it is).

Why is there a comma before onko?

In Finnish, you must use a comma to separate the main sentence from an indirect question. English usually drops the comma before "if" or "whether" in these sentences, but Finnish punctuation rules strictly require it.

Why do tällä and kierroksella have the -lla/-llä endings instead of the -ssa/-ssä endings for "in"?

English says "in this round", but Finnish treats a "round" (like in a game) as an abstract surface or period, requiring the adessive ending -lla/-llä (which usually means "on" or "at"). The word tämä (this) has to match the ending of the noun it describes, so it becomes tällä.

How does the base word kierros (round) become kierroksella?