Learn Hardcore Finnish: Sen kymmenes kerros avataan yleisölle ensi viikolla. - Its tenth floor will be opened to the public next week.

Sen is the genitive form of the pronoun se (“it” or “that”). Here it refers back to a previously mentioned building or structure. So Sen kymmenes kerros literally means “the building’s tenth floor.”

Why is the number written as kymmenes instead of kymmenen?

Kymmenes is the ordinal number “tenth,” while kymmenen is the cardinal “ten.” We use an ordinal because we’re specifying which floor (“the tenth floor”), not counting floors.

How do ordinals like kymmenes agree with the noun they modify?

Ordinals in Finnish inflect like adjectives. They must match the noun in case, number, and (when relevant) gender. Here kerros is in the nominative singular, so we use kymmenes kerros in nominative singular. If you needed a different case, the ordinal would change too (e.g. “of the tenth floor” = kymmenennen kerroksen).

What is the role of avataan in this sentence?

Avataan is the present-passive form of avata (“to open”). Finnish uses passive when the agent of the action is unspecified or unimportant. So avataan means “is opened” or “will be opened” without naming who does the opening.

Does avataan mean “is opened” or “will be opened”?

Finnish does not have a separate future tense, and the present-passive can cover both present and future meanings. In context—talking about a scheduled event—it translates best as “will be opened.”

Why is yleisölle in the -lle form?

Yleisölle is the allative/dative case of yleisö (“public” or “audience”), marked by -lle to indicate direction to someone. So avataan yleisölle means “is opened to the public.”

Why does ensi viikolla use the -lla ending on viikko?

Time expressions indicating “during” or “within” a period take the inessive case -ssa/ssä or the adessive case -lla/llä. With viikko, viikolla (adessive) is standard for “next week” (literally “on next week” or “during next week”).