Learn Hardcore Finnish: Käyn metsässä harvoin, vaikka luonto kiinnostaa minua. - I visit the forest rarely, even though nature interests me.

käyn is the 1st person singular present tense of the verb käydä (to go/visit). In Finnish you don’t need the pronoun minä because the verb ending -n already tells you that the subject is “I.”

Why is there no minä before käyn?

Finnish is a pro-drop language: subject pronouns are optional when the verb ending makes the person clear. Adding minä would be grammatically correct but redundant.

What does the ending -ssä in metsässä indicate?

The suffix -ssä marks the inessive case, which expresses location (“in”). So metsässä literally means “in the forest.”

Why is harvoin used instead of an adjective like harva?

harvoin is an adverb meaning “rarely.” Adjectives (like harva) modify nouns, whereas adverbs modify verbs or describe the manner/frequency of an action.

Why is harvoin placed after metsässä instead of at the very beginning of the sentence?

Finnish word order is fairly flexible. Placing metsässä before harvoin puts the emphasis on location first, then on frequency. You could also say Harvoin käyn metsässä, which shifts the focus slightly toward how rarely you go.

Why is there a comma before vaikka?

vaikka introduces a subordinate concession clause (“although…”). Finnish grammar requires a comma between the main clause and a subordinate clause.

Why does the vaikka clause use the indicative form kiinnostaa instead of something like a subjunctive or conditional?

When vaikka expresses a real concession (something that’s actually true), the verb stays in the indicative mood. You’d use a conditional or subjunctive only if you were talking about a hypothetical concession.

In luonto kiinnostaa minua, why is luonto in the nominative case and minua in the partitive?

Finnish structures interest the opposite way from English: the thing that interests is the grammatical subject (nominative luonto), and the person who feels the interest is the object. Verbs like kiinnostaa take their object in the partitive, hence minua (“me”).

Could you replace vaikka with mutta here? What would change?

Yes, you could say Käyn metsässä harvoin, mutta luonto kiinnostaa minua.
Using mutta (“but”) links two main clauses and simply contrasts them. vaikka (“although”) makes the second clause subordinate and emphasizes that your interest in nature persists despite going to the forest rarely.