Learn Hardcore Finnish: Kun huoltomies kiinnitti johdon, kahvinkeitin alkoi taas porista. - When the maintenance man attached the cable, the coffee maker started to gurgle again.

huoltomies literally means “maintenance man” or “service technician.” It’s a compound noun made from huolto (“maintenance, servicing”) + mies (“man”).

Why is johdon in the genitive case instead of nominative?

In Finnish, many transitive verbs take their direct object in the “accusative” case, which in singular looks exactly like the genitive. The verb kiinnittää (“to attach/fasten”) is one of them, so johto (“cord”) becomes johdon.

Why does the sentence start with Kun, and why is there a comma after johdon?

Kun here means “when” and introduces a temporal subordinate clause. In Finnish, a subordinate clause that comes before the main clause is separated by a comma.
Structure:
Kun-clause , main clause.

What tense and form is kiinnitti, and why is it used here?

Kiinnitti is the imperfect (simple past) form of kiinnittää. It tells us the action of fastening the cord happened once in the past.

What does taas mean in this context?

Taas means “again.” It signals that the coffee maker had been gurgling before, stopped, and now started gurgling once more.

What does alkoi porista mean, and why use two verbs?

Alkoi is the imperfect of alkaa (“to begin”). Porista is the infinitive/basic form of porista (“to gurgle”).
Many Finnish verbs of beginning or continuing (alkaa, jatkaa, lopettaa) combine with a second verb in basic form, so alkoi porista = “began to gurgle.”

What kind of verb is porista, and where does it come from?

Porista is an onomatopoetic verb deriving from porina (“gurgling, purring sound”). It describes the characteristic sound of the coffee machine working.