Learn Hardcore Finnish: Tarvitsen hissin, koska kannan raskaan laatikon viidenteen kerrokseen. - I need the elevator because I carry a heavy box to the fifth floor.

Finnish verbs include person and number in their endings, so the pronoun minä (“I”) is optional. The -n ending on tarvitsen and kannan already signals that the subject is minä, making the pronoun unnecessary in most contexts.

Why is hissin used instead of hissi (nominative) or hissiä (partitive)?

When you need a specific, whole object, Finnish uses the accusative (sometimes called the object case), which in singular looks like the genitive ending -n. So tarvitsen hissin means “I need the elevator” as one distinct item. The partitive hissiä would imply an unspecified amount or an incomplete action, like “I need some elevator (some of it).”

Why does raskas laatikko become raskaan laatikon in the sentence?

Adjectives in Finnish agree with the nouns they modify in both case and number. Here the object is singular and treated as a complete, specific entity, so it takes the accusative/genitive case: raskas → raskaan, laatikko → laatikon.

What case is viidenteen kerrokseen, and how does it work?

It’s the illative case, which indicates motion “into” something. The suffix -seen marks this case. Both words are inflected: viides (“fifth”) → viidenteen, kerros (“floor”) → kerrokseen. Together they literally mean “into the fifth floor.”

How do you form the illative case for ordinal numbers and nouns in general?

For most singular nouns, attach -seen to the stem (e.g. kerros → kerros-
- -seen → kerrokseen).
Ordinal numbers like kolmas, neljäs, viides have stems that take -teen: viiden
- -teen → viidenteen.
  Always watch for consonant gradation (e.g. k → kk) and vowel harmony in the stem.

What’s the function of koska in this sentence, and could you use sillä instead?

Koska is a conjunction meaning “because,” introducing a reason clause. You can also start the clause with sillä (“for/since”):
Tarvitsen hissin, sillä kannan raskaan laatikon viidenteen kerrokseen.
Koska is more neutral; sillä often feels slightly more formal or explanatory.

Can you swap the main clause and the reason clause? How about the comma?

Yes. You can say:
Koska kannan raskaan laatikon viidenteen kerrokseen, tarvitsen hissin.
The comma stays between the clauses. Finnish word order is quite flexible, so both orders are correct and understandable.

Why does kantaa become kannan with two n’s in kannan raskaan laatikon?

The verb kantaa belongs to a type that undergoes consonant gradation. In the infinitive the stem is kanta-, but when you add the first-person singular ending -n, the nt weakens to nn:
kanta- + -n → kannan.