Hun venter ved receptionen, mens jeg går ned ad trappen.

Because hun is the subject form of she.

In Hun venter ved receptionen, hun is the person doing the action, so Danish uses hun.

Compare:

• Hun venter. = She is waiting.
• Jeg ser hende. = I see her.

So:

• hun = she
• hende = her

Venter is the present tense of vente = to wait.

Danish usually uses the simple present where English often uses either:

• waits
• is waiting

So Hun venter can mean:

• She waits
• She is waiting

In this sentence, the natural English translation is usually She is waiting because it describes what is happening now.

Ved often means at, by, or near.

So ved receptionen suggests she is at the reception desk/area, probably standing there waiting.

By contrast:

• i receptionen = in the reception area

That can also be possible in other contexts, but ved receptionen focuses more on being at that specific point or desk.

So this sentence is probably saying she is waiting at the reception desk rather than simply somewhere inside the reception area.

Because Danish usually puts the definite article at the end of the noun.

So:

• en reception = a reception / a reception desk
• receptionen = the reception / the reception desk

This is very different from English, where the is a separate word.

Other examples:

• en trappe = a staircase
• trappen = the staircase

Mens means while.

It connects two actions that happen at the same time:

• Hun venter ved receptionen
• mens jeg går ned ad trappen

So the idea is:

• She is waiting at the reception desk while I walk down the stairs.

Mens is a very common word for simultaneous actions.

Because mens introduces a subordinate clause, and in Danish subordinate clauses the word order is normally:

conjunction + subject + verb

So:

• mens jeg går
• while I walk / while I am walking

That is normal Danish word order after mens.

A useful comparison:

• Main clause: Jeg går ned ad trappen.
• Subordinate clause: ..., mens jeg går ned ad trappen.

In this example, the order stays jeg går.

Because Danish normally uses a comma before a subordinate clause like one introduced by mens.

So:

• Hun venter ved receptionen, mens jeg går ned ad trappen.

This comma is standard in Danish writing.

English also often uses a comma before while in similar sentences, though the rules are not always identical.

It means goes/walks down the stairs or down the staircase.

This expression has three parts:

• går = goes / walks
• ned = down
• ad trappen = movement along/down the staircase

Together, gå ned ad trappen is a very natural Danish way to say walk down the stairs.

Here ad is used for movement along something, especially a path, surface, or route.

So:

• ned ad trappen = down the stairs
• op ad trappen = up the stairs

You also see ad in things like:

• gå ad vejen = walk along the road
• cykle ad stien = cycle along the path

For English speakers, ad in this use is often best understood as part of the whole expression rather than translated word-for-word.

In standard Danish, ned ad trappen is the usual expression for going down the stairs.

The difference is roughly:

• ad = movement along something
• af = movement off/from something

So:

• gå ned ad trappen = walk down the stairs
• gå af trappen would suggest something more like step off the staircase, which is not the normal meaning here

In everyday speech, some speakers may blur or mix ad and af, but learners should use ned ad trappen as the standard form.

Because trappen is singular definite:

• en trappe = a staircase / a stairway
• trappen = the staircase

Even though English often says the stairs, Danish very often uses singular trappe where English uses a plural form.

So:

• gå ned ad trappen = literally go down the staircase
• natural English: go down the stairs

If there were multiple staircases, then plural might make sense:

• trapperne = the staircases

But here it is just one staircase/stairway.

Yes. That is completely normal.

In this sentence, both verbs are in the present tense:

• venter
• går

Danish does not usually need a special form like English is waiting or am walking to show an action is in progress.

So Danish often uses the plain present where English uses the progressive:

• Hun venter = She is waiting
• jeg går ned ad trappen = I am walking down the stairs

Yes.

You can say:

• Mens jeg går ned ad trappen, venter hun ved receptionen.

That means the same thing.

But notice the word order in the main clause after the fronted subordinate clause:

• ..., venter hun ...

The verb comes before the subject in the main clause because Danish uses V2 word order in main clauses.

So compare:

• Hun venter ved receptionen, mens jeg går ned ad trappen.
• Mens jeg går ned ad trappen, venter hun ved receptionen.

Both are correct.

Not necessarily.

Receptionen can mean the reception, often understood as:

• the reception desk
• the front desk
• the reception area

The exact meaning depends on context. It could be in:

• a hotel
• an office
• a clinic
• a company building

So learners should think of it as the reception/front desk area, not only a hotel.

A rough pronunciation guide for an English speaker could be:

• Hun ≈ hoon or a short hun with a very reduced vowel depending on accent
• venter ≈ VEN-dor / VEN-ter with a soft Danish t
• ved ≈ vel with a soft d
• receptionen ≈ reh-sep-sho-nən
• mens ≈ mens
• jeg ≈ yai or yai/yei depending on accent
• går ≈ something like gor with a more open vowel
• ned ≈ nel with soft d
• ad ≈ a with a very soft or almost silent d
• trappen ≈ TRAP-en

The hardest parts for English speakers are usually the soft d in words like ved, ned, and ad, and the vowel sounds in words like går.