Learn Hardcore Finnish: Terassilla on lamppu, joka antaa pehmeää valoa. - On the terrace there is a lamp that gives soft light.

Terassilla is the adessive singular form of terassi. The adessive case (–lla/–llä) marks location “on” or “at” a surface. Here it tells us that the lamp is located on the terrace.

Why is lamppu in the nominative case instead of the partitive?

In existential constructions (there is/are), a single indefinite item appears in the nominative: “Terassilla on lamppu” = “There is a lamp on the terrace.” If you had multiple lamps, you’d say “Terassilla on lamppuja” (partitive plural) for “there are lamps.”

What does the verb on mean in this sentence?

On is the third-person singular present form of olla (“to be”). In existential sentences it functions like English “there is” or “there are.” So “Terassilla on lamppu” = “There is a lamp on the terrace.”

What is the function of joka here? Could I use mikä instead?

Joka is a relative pronoun referring back to lamppu (“which that lamp”). It introduces the clause “which gives soft light.” You generally use joka after a specific noun. Mikä can only replace a whole idea or refer back to a pronoun, not directly to a concrete noun like lamppu.

Why do we say pehmeää valoa instead of pehmeä valo?

The verb antaa (“to give”/“emit”) takes its object in the partitive when the action involves an indefinite or unquantified amount. Here you’re talking about an unspecified amount of soft light, so both pehmeä and valo get the partitive ending: pehmeää valoa.

How does the adjective pehmeä change to agree with the noun in the partitive?

In the partitive singular, the adjective pehmeä takes an extra –ää: pehmeä → pehmeää. The noun valo similarly becomes valoa. Together you get pehmeää valoa.

Why is there a comma before joka? Is it required?

The comma signals a non-restrictive (non-defining) relative clause—adding extra info about the lamp rather than distinguishing it from other lamps. In Finnish you can omit the comma if the clause is restrictive (essential to identify the noun). Here it’s optional, but the comma is common for clarity.

Could I rephrase the sentence as Lamppu terassilla antaa pehmeää valoa? How would that change the emphasis?

Yes. “Lamppu terassilla antaa pehmeää valoa” is a straightforward SVO (subject-verb-object) sentence: “The lamp on the terrace gives soft light.” The original existential “Terassilla on lamppu…” emphasizes the existence/location first (“On the terrace there is a lamp…”), then adds what it does.

What nuance does pehmeä add when describing valo?

Literally pehmeä means “soft.” With valo, it conveys gentle, diffused, or mellow lighting—think of a warm, cozy glow rather than a harsh beam.

Why not use terassissa instead of terassilla?

Terassissa (inessive case) means “inside the terrace,” which is unusual since a terrace is normally an open, surface-like space. Terassilla (adessive) correctly means “on the terrace,” fitting this context.