Hun har det med at svare meget kort, når hun er træt, men hun er stadig venlig.

It is a common Danish expression meaning to tend to, to have a habit of, or to be prone to doing something.

So:

• Hun har det med at svare meget kort
  = She tends to answer very briefly

It suggests a repeated pattern, not just a one-time action.

In this expression, det is part of a fixed idiom. You usually should learn have det med at + infinitive as one chunk.

So even though det literally means it, here it is not translated separately in a natural English way.

Examples:

• Jeg har det med at glemme navne.
  = I tend to forget names.
• Han har det med at komme for sent.
  = He tends to arrive late.

Because after har det med at, Danish uses the infinitive form.

Structure:

• har det med at + infinitive

So:

• at svare = to answer

Not:

• har det med svarer ❌

Compare:

• Hun svarer meget kort.
  = She answers very briefly.
  This is a normal main clause.

• Hun har det med at svare meget kort.
  = She tends to answer very briefly.
  This uses the fixed expression.

Here kort functions adverbially, meaning briefly or in a short way.

In Danish, many adjectives can also be used as adverbs without changing form much in this kind of sentence.

So:

• svare kort = answer briefly
• svare meget kort = answer very briefly

You are describing how she answers, not describing a noun.

Compare:

• et kort svar = a short answer
  Here kort describes the noun svar.
• hun svarer kort = she answers briefly
  Here kort describes the verb/action.

Because kort here is not modifying a plural noun. It is describing the manner of the action svare.

• meget = very
• kort = briefly / short

So meget kort means very briefly.

If you were describing plural nouns, then you might use korte:

• korte svar = short answers

But in your sentence, she is not producing short answers as a noun phrase; she is answering briefly.

Here når means when.

• når hun er træt = when she is tired

It is used because the sentence describes something that typically happens in that situation.

Compare:

• når = when / whenever
• hvis = if

So:

• Hun svarer kort, når hun er træt.
  = She answers briefly when she is tired.
  This describes a usual pattern.

• Hun svarer kort, hvis hun er træt.
  = She answers briefly if she is tired.
  This sounds more conditional: if that situation happens.

In many everyday contexts, the difference can be small, but når fits this habitual meaning very well.

Because når hun er træt is a subordinate clause.

In Danish subordinate clauses, the word order is generally:

• conjunction + subject + verb + other elements

So:

• når = when
• hun = she
• er = is
• træt = tired

This is normal subordinate clause order.

If the subordinate clause came first, the main clause after it would show inversion:

• Når hun er træt, svarer hun meget kort.

Notice that after the fronted clause, Danish puts the verb before the subject in the main clause:

• svarer hun
  not
• hun svarer

But in your original sentence, the subordinate clause comes later, so the first main clause keeps normal order.

Stadig means still and usually comes in the normal adverb position, often after the finite verb and before the adjective or main description.

So:

• hun er stadig venlig
  = she is still friendly

Breakdown:

• hun = she
• er = is
• stadig = still
• venlig = friendly

This is the natural word order in Danish.

Because venlig agrees with the subject in a predicate adjective construction.

Here the subject is hun, referring to one person, so the adjective takes the common singular form:

• hun er venlig = she is friendly

Compare:

• det er venligt = that/it is kind
  Neuter singular often takes -t
• de er venlige = they are friendly
  Plural takes -e

So in your sentence, venlig is the correct form.

For the same reason as venlig: it is a predicate adjective referring to hun.

• hun er træt = she is tired

Since the subject is singular and refers to a person, the basic form træt is used.

Compare:

• et barn er træt / sometimes adjective agreement may vary depending on form, but with træt as predicate for a neuter noun you would often still see træt in common usage
• de er trætte = they are tired

The important form to remember here is:

• hun er træt

Because Danish, like English, normally requires each clause to have its own subject.

The sentence has more than one clause:

1. Hun har det med at svare meget kort
2. når hun er træt
3. men hun er stadig venlig

Each clause needs its own subject where appropriate, so hun appears again.

This is completely normal and natural.

Men means but. It connects two main ideas in contrast:

• She tends to answer very briefly when she is tired,
• but she is still friendly.

So the sentence is balancing two things:

• her answers may be short,
• but her attitude is still kind.

Yes, but the meaning changes a little.

• Hun svarer meget kort, når hun er træt.
  = She answers very briefly when she is tired.
• Hun har det med at svare meget kort, når hun er træt.
  = She tends to answer very briefly when she is tired.

The version with har det med at sounds more like a recurring tendency or habit. The shorter version is more direct and neutral.

Yes. At svare kort is a very natural way to say to answer briefly, to answer shortly, or sometimes to answer curtly, depending on context.

Important nuance:

• kort can be neutral: just brief
• in some contexts it can sound slightly negative: abrupt or curt

In your sentence, the second half — men hun er stadig venlig — helps show that her short answers are not meant as rudeness.