Learn Hardcore Norwegian: Sentrumet er rolig i kveld.

Grammatically, sentrumet is the definite singular (the centre), and it’s correct Bokmål. However, in everyday Norwegian people often talk about downtown as a place name and skip the article:

Sentrum er rolig i kveld.
Det er rolig i sentrum i kveld. (very natural)

Using sentrumet is not wrong, but many would prefer one of the two alternatives above unless you’re contrasting with another specific centre.

What gender is sentrum, and what are its forms?

Sentrum is neuter.

Indefinite singular: et sentrum
Definite singular: sentrumet
Indefinite plural: sentra (common) or sentrum (also accepted)
Definite plural: sentrene (from sentra) or sentrumene (from sentrum)

Why isn’t it roligt since sentrumet is neuter?

Adjectives ending in -ig/-lig/-sk usually do not take the neuter -t, either attributively or predicatively. So you say:

et rolig sted (not roligt)
Sentrumet er rolig (not roligt)

Compare with adjectives that do take -t:

et stort hus / Huset er stort
et nytt hotell / Hotellet er nytt

What’s the difference between rolig and stille?

rolig = calm/peaceful/uneventful. It’s about mood, activity level, traffic, pace.
- Det er rolig i sentrum. (few people, little going on)
stille = quiet/silent (about sound).
- Det er stille i sentrum. (little noise) You can combine them: rolig og stille.

Can I move i kveld to the front? Any word-order rule?

Yes: I kveld er sentrumet rolig. Norwegian main clauses follow the V2 rule: if you front an element (here, a time adverbial), the finite verb stays in second position.

What’s the most natural way to say this?

Many would prefer:

Det er rolig i sentrum i kveld. This uses dummy det and puts the place in a prepositional phrase, which is very idiomatic.

Why is the preposition i used for both place and time here?

Because i often means “in/at” for both:

Place: i sentrum (in the city centre)
Time: i kveld (this evening/tonight) Note: for days and parts of the day in a habitual/generic sense, use om/på:
om kvelden / på kvelden = in the evenings (habitually)
på fredag = on Friday

Should kveld be definite here?

No. It’s the fixed time expression i kveld (tonight/this evening). Don’t say i kvelden in standard Bokmål. For a general/habitual meaning, use om kvelden/på kvelden.

How do I make the yes/no question?

Two natural options:

Er sentrumet rolig i kveld?
Er det rolig i sentrum i kveld? (often sounds more natural)

If I mean “will be quiet tonight,” should I use blir?

Yes, blir is the idiomatic choice for near-future/result:

I kveld blir det rolig i sentrum. You can use vil være, but blir is more common in such forecasts.

Is Sentrum capitalized?

Only because it starts the sentence. sentrum is a common noun and is not capitalized mid-sentence: Det er rolig i sentrum.

Any quick pronunciation tips?

sentrumet: many speakers don’t pronounce the final -t clearly, so it can sound like “sentrum-e.”
rolig: the final g is often weak or silent; many say it like “ro-li.”
i kveld: the d in kveld is often silent; it sounds like “kvell.” Regional variation exists; these are common patterns.

Is ikveld ever written as one word?

No. Standard spelling is two words: i kveld.

Can I say Byens sentrum er rolig i kveld?

Yes. Byens sentrum specifies which city’s centre you mean. It’s useful if context isn’t clear:

Byens sentrum er rolig i kveld.
Also natural: Det er rolig i byens sentrum i kveld.

Where does negation go?

After the verb (and subject) in a main clause:

Sentrumet er ikke rolig i kveld. With fronting (V2 still applies):
I kveld er sentrumet ikke rolig. Or the very natural dummy-subject variant:
Det er ikke rolig i sentrum i kveld.