Learn Hardcore Danish: Min bror må ikke låne bilen i aften. - My brother may not borrow the car tonight.

In this sentence, må expresses permission. With ikke, må ikke means “is not allowed to” or “mustn’t.” So: “My brother is not allowed to borrow the car tonight.” Note that in Danish, må ikke is prohibition, not uncertainty; it does not mean “might not.”

What’s the difference between må ikke and kan ikke?

må ikke = not permitted: “Han må ikke låne bilen” = “He is not allowed to borrow the car.”
kan ikke = not able/possible: “Han kan ikke låne bilen” = “He can’t borrow the car” (e.g., no car available, no license, or some practical impossibility).
Use må for permission, kan for ability/possibility.

How does må ikke compare with skal ikke and behøver ikke?

må ikke: prohibition/permission denied. “You mustn’t/are not allowed to …”
skal ikke: either “you are not to/shouldn’t …” (instruction) or “don’t have to” depending on context. It can sound directive and is less clearly about permission than må ikke.
behøver ikke (at): lack of necessity, “don’t need to/don’t have to,” not a ban.
For clear prohibition, prefer må ikke (or “får ikke lov til at …”).

Why is there no at before låne?

Danish modal verbs (e.g., må, kan, skal, vil, bør) take the bare infinitive without at. Hence: må låne, not “må at låne.”

Why is ikke placed between må and låne?

In main clauses, Danish is V2: the finite verb (må) is in second position. Negation ikke typically comes after the finite verb and before the infinitive: må ikke låne.
In a subordinate clause, ikke comes earlier: “(at) min bror ikke må låne bilen i aften.”

Why is the present tense used for a future time (i aften)?

Danish commonly uses the present tense with a time expression to talk about near-future plans: … må ikke … i aften = “is not allowed to … tonight.” There’s no dedicated future tense needed.

What’s the difference between i aften, i nat, and i aftes?

i aften: this evening/tonight (the evening period later today)
i nat: tonight/last night (the nighttime period, often when people sleep)
i aftes: last evening (yesterday evening)

How does i aften differ from om aftenen?

i aften = this specific evening (tonight).
om aftenen = in the evenings (habitually, as a general time of day).
You wouldn’t say “i aftenen” for “in the evening” in this sentence.

Does låne mean “borrow” or “lend”?

Both, depending on the construction:

borrow: låne noget (af nogen) — “borrow something (from someone).”
Example: “Jeg vil låne bilen af dig.”
lend: låne nogen noget — “lend someone something.”
Example: “Vil du låne mig din bil?”
In your sentence, låne bilen = “borrow the car” (from context).

Why bilen (“the car”) and not min bil (“my car”)? Does bilen imply it’s mine?

bilen just means “the car” (a specific, context-known car). It could be the family car, my car, or someone else’s car previously mentioned. If you want to specify ownership, say min bil.
Form reminder: en bil (a car) → bilen (the car) → biler (cars) → bilerne (the cars).

Why Min bror and not Mit/Mine bror?

Possessives agree with the noun’s gender/number:

min for common-gender singular nouns (e.g., bror, bil)
mit for neuter singular nouns (e.g., hus → mit hus)
mine for all plurals (e.g., brødre → mine brødre).
Since bror is common gender and singular, it’s min bror.

How do I say this in the past?

Use the past of må, which is måtte:

Min bror måtte ikke låne bilen i går. = “My brother wasn’t allowed to borrow the car yesterday.”

Are there alternative ways to express “not allowed” in Danish?

Yes:

Min bror får ikke lov til at låne bilen i aften.
Min bror har ikke lov til at låne bilen i aften.
These explicitly mention permission (“get/have permission”) and are interchangeable with må ikke in many contexts.

Can I move elements for emphasis, like i aften or bilen?

Yes, by topicalization, keeping V2:

I aften må min bror ikke låne bilen. (emphasizes “tonight”)
Bilen må min bror ikke låne i aften. (emphasizes “the car”)
Meaning stays the same; the focus changes.

Any quick pronunciation tips for the tricky words?

Very rough guides:

må ≈ “maw” with a rounded vowel (don’t say “may”)
bror ≈ “broar” (Danish r is guttural; the vowel is like “o” in “more”)
ikke ≈ “IK-keh” (often reduced in fast speech)
låne ≈ “LOH-neh” (long “oh” sound)
bilen ≈ “BEE-len”
aften ≈ “AF-ten” (the “t” may feel softened in fast speech)