Lyskontakten i gangen sidder så højt, at min datter ikke kan nå den alene.

Danish very often forms compound nouns as a single word.

• lys = light
• kontakt = switch/contact

So lyskontakt means light switch.

Then -en is added because the noun is in the definite singular:

• en lyskontakt = a light switch
• lyskontakten = the light switch

This is very normal in Danish. English often uses separate words where Danish prefers one compound word.

Because both are common-gender singular definite nouns.

• en lyskontakt → lyskontakten = the light switch
• en gang → gangen = the hallway / corridor

In Danish, the definite article is usually added to the end of the noun instead of being a separate word like English the.

So:

• i gangen = in the hallway
• lyskontakten = the light switch

Because Danish often uses the definite form for places when talking about a specific room or area in a home.

So:

• i gangen = in the hallway
• i køkkenet = in the kitchen
• i stuen = in the living room

This is often more natural than an indefinite form in this kind of sentence.

In Danish, verbs like sidde, stå, and ligge are often used to describe where something is located, not just body position.

Here, sidder means something like:

• is mounted
• is positioned
• is located

So Lyskontakten i gangen sidder så højt means: The light switch in the hallway is placed so high...

This is very idiomatic Danish. Using er would be possible in some contexts, but sidder sounds more natural for something attached to a wall.

Here højt functions adverbially, describing how high the switch is positioned, not directly describing the noun as an adjective before a noun.

Compare:

• en høj væg = a high wall
• kontakten sidder højt = the switch is positioned high

In this kind of use, Danish often uses the -t form of the adjective as an adverb:

• høj → højt
• lav → lavt
• god → godt

So så højt means so high.

Så ... at means so ... that.

In the sentence:

• så højt = so high
• at min datter ikke kan nå den alene = that my daughter cannot reach it by herself

So the structure is:

• så + adjective/adverb + at + clause

Examples:

• Han er så træt, at han går i seng nu. = He is so tired that he is going to bed now.
• Det er så dyrt, at jeg ikke vil købe det. = It is so expensive that I do not want to buy it.

Because after at, Danish uses subordinate clause word order.

In a subordinate clause, words like ikke usually come before the finite verb.

So:

• min datter ikke kan nå den alene

not

• min datter kan ikke nå den alene

Compare:

Main clause

• Min datter kan ikke nå den.

Subordinate clause

• ... at min datter ikke kan nå den.

This is one of the most important word-order patterns in Danish.

Here nå means to reach in a physical sense.

So:

• kan nå den = can reach it

It can also have other meanings in Danish depending on context, such as arrive in time or manage to get to, but in this sentence it clearly means physically reach with the hand/body.

Because lyskontakt is a common-gender noun:

• en lyskontakt

Common-gender nouns are referred to with den.

Compare:

• en stol → den
• en lyskontakt → den
• et bord → det

So nå den means reach it, where it refers to lyskontakten.

Here alene means alone or by herself.

So:

• min datter ikke kan nå den alene = my daughter cannot reach it by herself

It suggests that she might be able to reach it with help, but not on her own.

Sometimes learners wonder about this because English often uses herself.

In this sentence, alene is the natural choice because it means on her own / without help.

• ikke kan nå den alene = cannot reach it by herself

Selv often means self, even, or adds emphasis, and it would not be the best choice here in the same way.

So if you want to express without help, alene is the right word.

That whole phrase is the subject of the sentence:

• Lyskontakten i gangen = the light switch in the hallway

Inside that subject:

• lyskontakten is the main noun
• i gangen tells you which light switch

So the structure is:

• [Subject] Lyskontakten i gangen
• [Verb] sidder
• [Rest] så højt, at min datter ikke kan nå den alene

Yes. Min is the possessive form used with a common-gender singular noun.

• min datter = my daughter
• min stol = my chair

Compare:

• mit barn = my child (et-word)
• mine børn = my children (plural)

Since datter is an en-word, min is correct.