Learn Finnish: Me vertailimme uuden juhlapaikan tarjoilupöytiä kaksissa polttareissa. - We compared the new party venue's serving tables at two bachelor parties.

The word for a bachelor party, polttarit, is a plural-only noun in Finnish. When you count plural-only nouns, the number itself must also be in the plural and match the noun's case. Since the sentence says "at" two bachelor parties, both the number and the noun take the plural inessive ending: kaksissa polttareissa.

Is polttarit always a plural word, even when referring to just one bachelor party?

Yes. Just like the words for weddings (häät) and funerals (hautajaiset), the Finnish word for a bachelor or bachelorette party (polttarit) is always grammatically plural. If you were talking about a single party, you would use the plural form of the number one: yhdet polttarit.

Why is tarjoilupöytiä in the partitive plural? Shouldn't it be an object in the accusative?

The verb vertailla (to compare) requires a partitive object. This is because comparing is viewed as an ongoing or continuous process rather than a completed action with a strict endpoint. Therefore, the serving tables take the partitive plural form: tarjoilupöytiä.

How do you build the partitive plural tarjoilupöytiä from its base form?