Learn Hardcore Norwegian: Det er enklere å sove når det er stille.

The first det is a dummy/expletive subject that fills the subject slot in Det er enklere ... (just like English “It is easier ...”). The second det in når det er stille is the subject of the subordinate clause (“when it is quiet”), again the generic ambient “it.”

Can I drop the second det and say når er stille?

No. Norwegian subordinate clauses need an explicit subject, so you must keep det: når det er stille.

What is å here, and why not og?

Å is the infinitive marker “to” before a verb: å sove = “to sleep.” Og means “and” and cannot mark an infinitive. So write enklere å sove, not enklere og sove.

Why enklere and not mer enkel?

Most short/common adjectives form the comparative with -ere. Enkel → enklere is the natural choice. Mer enkel exists but sounds marked/less idiomatic here. You could also use the near-synonym lettere (“easier”): Det er lettere å sove ... (very common).

Is there a difference between sove and sovne?

Yes:

sove = “to sleep” (the state)
sovne = “to fall asleep” (the transition) If you mean “fall asleep,” say: Det er enklere å sovne når det er stille.

Why is it når and not da?

Use når for general/habitual time and for the present/future (“when(ever)”). Use da for a single, specific past event. Here it’s a general statement, so når is correct. Past, one-time: Det var enklere å sove da det var stille.

What’s the word order rule here? Could I front the time clause?

Main clauses are verb-second: Det (1) er (2) enklere .... In the subordinate clause, the verb is not forced to second: når det er stille. You can front the time clause: Når det er stille, er det enklere å sove. Note the comma after the fronted clause. No comma is needed in the original order.

Is stille an adjective or an adverb here?

In det er stille, stille is a predicate adjective meaning “quiet.” The same form can also act adverbially in other contexts (e.g., gå stille “walk quietly”), but here it describes the state of the environment.

Where does ikke go if I want to negate parts of the sentence?

Negate the main statement: Det er ikke enklere å sove når det er stille.
Negate the time clause: Det er enklere å sove når det ikke er stille.
Negate the infinitive: Det er enklere å ikke sove (“It’s easier not to sleep”). In an infinitive phrase, ikke typically comes right before the verb: å ikke sove.

Can I say Å sove er enklere når det er stille?

Yes. Fronting the infinitive clause is correct and slightly more topic-focused: Å sove becomes the topic. Both orders are natural.

Could I use blir instead of er?

Yes, with a nuance: Det blir enklere å sove når det er stille = “It becomes/gets easier to sleep when it’s quiet,” emphasizing a change or comparison to a less quiet situation.

What about the superlative: enklest?

It’s grammatical: Det er enklest å sove når det er stille. That suggests “of all situations, the easiest is when it’s quiet,” a stronger, more contrastive claim than the comparative.

Are there natural alternatives to stille?

rolig = “calm/quiet” (broader, also about atmosphere): når det er rolig.
helt stille = “completely quiet/silent.”
Noun option: i stillhet (“in silence”): Det er enklere å sove i stillhet. Each has a slightly different nuance but all work.

Is there any ambiguity with lettere and sove?

Be careful with placement:

Det er lettere å sove = “It’s easier to sleep” (good).
å sove lettere would mean “to sleep more lightly” (a different meaning: not deep sleep).

Do I ever need for å here?

Not in this sentence. For å expresses purpose (“in order to”): Jeg lukker vinduet for å sove (“I close the window in order to sleep”). Your sentence describes a condition, not a purpose.

Can I replace the whole time clause with a noun phrase?

Yes, with a stylistic shift: Det er enklere å sove i ro/stillhet. You’ll often see phrases like i ro og fred (“in peace and quiet”): Det er enklere å sove i ro og fred.

How do I pronounce it?

Approx. Standard Eastern Norwegian:

Det er enklere å sove når det er stille ≈ [deːt æːr ˈɛŋklərə oː ˈsuːʋə nɔr deːt æːr ˈstɪlːə] Tips: stress ENK- in enklere, long vowel in sove (SO-), double L in stille gives a clear, short vowel before it.

Is the form enklere invariable here?

Yes. In predicate comparative position (after er), adjectives don’t agree for gender/number: it’s always enklere here, regardless of any implied subject.

Is this Bokmål? What would Nynorsk look like?

Yes, it’s Bokmål. In Nynorsk you’d typically write: Det er enklare å sove når det er stille. (Comparative ending -are is standard in Nynorsk.)