Min tandpasta ligger bag spejlet, men min søsters tandbørste står stadig ved håndvasken.

This is one of the most important things for English speakers to notice in Danish.

Danish often prefers position verbs where English would simply use is or are.

• ligger = lies / is lying
• står = stands / is standing

So:

• Min tandpasta ligger bag spejlet
  literally: My toothpaste lies behind the mirror
• Min søsters tandbørste står stadig ved håndvasken
  literally: My sister’s toothbrush stands still/by the sink

Why those verbs?

• tandpasta is thought of as something lying horizontally or just resting somewhere
• tandbørste is thought of as standing upright

In natural English, you usually translate both with is, but in Danish, choosing the right position verb sounds much more natural.

Because Danish is using the definite form: the mirror and the sink.

Danish usually adds the definite article to the end of the noun:

• et spejl = a mirror

• spejlet = the mirror

• en håndvask = a sink
• håndvasken = the sink

So:

• bag spejlet = behind the mirror
• ved håndvasken = by the sink

This is very normal in Danish. Instead of a separate word like the, Danish often attaches it to the noun.

In Danish, possession is usually shown by adding -s directly to the noun, without an apostrophe.

• min søster = my sister
• min søsters tandbørste = my sister’s toothbrush

So Danish writes:

• søsters

not

• søster’s

This is different from English spelling, but the idea is the same.

Because each possessed noun phrase needs its own possessor word.

The sentence has two separate noun phrases:

• Min tandpasta = my toothpaste
• min søsters tandbørste = my sister’s toothbrush

The first belongs to me, so it needs min.
The second also starts with my sister’s..., so it again needs min before søsters.

You cannot normally drop the second min here.

Because min is used with common gender nouns, and mit is used with neuter nouns.

• en tandpasta → common gender → min tandpasta
• en søster → common gender → min søster

If the noun were neuter, you would use mit:

• et spejl → mit spejl = my mirror

So the form of my changes depending on the grammatical gender of the noun.

Because in Danish, the definite article is usually attached to the end of the noun.

Compare:

• English: the mirror

• Danish: spejlet

• English: the sink
• Danish: håndvasken

So the -et and -en already mean the.

Danish can use a separate definite word like den/det, but usually only in certain structures, especially when an adjective comes before the noun:

• spejlet = the mirror
• det store spejl = the big mirror

Stadig means still.

So:

• står stadig ved håndvasken = is still standing by the sink

It suggests that the toothbrush is there as before, or remains there.

A few examples:

• Han sover stadig. = He is still sleeping.
• Jeg bor stadig i Aarhus. = I still live in Aarhus.

That is the normal word order here.

In a main clause, Danish usually puts the finite verb in second position. After that, adverbs such as stadig often come later.

So:

• min søsters tandbørste = subject
• står = finite verb
• stadig = adverb
• ved håndvasken = prepositional phrase

This gives:

• Min søsters tandbørste står stadig ved håndvasken.

That is the natural order.

They are different prepositions:

• bag = behind
• ved = by / near / at

So:

• bag spejlet = behind the mirror
• ved håndvasken = by the sink

Ved often means being next to something or in its immediate area.

Literally, it means behind the mirror.

But in everyday Danish, depending on the bathroom setup, it can naturally refer to something stored behind a mirrored cabinet door. So the exact physical interpretation can depend on context.

Still, grammatically, the phrase itself simply means behind the mirror.

Because Danish, like English, often forms compound nouns. In fact, Danish does this very frequently.

• tand = tooth
• børste = brush
• tandbørste = toothbrush

Likewise:

• tandpasta = toothpaste
• håndvask = literally something like hand-wash / washbasin, meaning sink

In Danish, these compounds are normally written as one word, not two.

A few helpful points:

• ø in søsters and tandbørste is a front rounded vowel that English does not really have
• å in håndvasken sounds somewhat like the vowel in British law, though not exactly
• Danish d and r can sound softer or less pronounced than English speakers expect

Very rough pronunciation guides:

• søsters ≈ SUR-sters but with a rounded vowel, not a normal English u
• tandbørste ≈ tahn-BUR-steh with that same rounded ø
• håndvasken ≈ HON-vask-en with å like a broad o

These are only approximations. The vowels are the hardest part for English speakers.

Men means but.

It connects two clauses:

• Min tandpasta ligger bag spejlet
• min søsters tandbørste står stadig ved håndvasken

So the whole sentence contrasts the location of the toothpaste with the location of the toothbrush:

• My toothpaste is behind the mirror, but my sister’s toothbrush is still by the sink.

Yes, you might hear er in some contexts, and it would be understandable:

• Min tandpasta er bag spejlet
• Min søsters tandbørste er ved håndvasken

But these sound less specifically Danish and less vivid than using ligger and står.

Using the position verbs is usually more natural when talking about where objects are physically located.

So:

• er = understandable, more neutral
• ligger / står = more idiomatic and natural

It means both of those in the sense that they are the same idea. In natural English, you would normally say:

• my sister’s toothbrush

Danish possession with -s works very much like the English ’s, just without the apostrophe.

So min søsters tandbørste is the normal, natural way to express that relationship.