Barnet vill ha sitt blå täcke på sängen varje natt.

Barn is the basic form, meaning child.
Barnet is the definite singular form, meaning the child.

• ett barn = a child
• barnet = the child

So the sentence starts with Barnet because it is talking about a specific child.

Yes. Swedish commonly uses vill + infinitive to mean want to do something.

So:

• vill ha = wants to have
• vill sova = wants to sleep
• vill läsa = wants to read

This is completely normal in Swedish. English often uses want + object or want to + verb, but Swedish often keeps the verb ha where English might not.

Because after vill, Swedish normally uses the infinitive without att.

• Barnet vill ha...
• Jag vill gå.
• Hon vill läsa.

This is like English can go, must eat, want to eat—except in Swedish, vill is followed directly by the infinitive.

Sin, sitt, sina are reflexive possessive words meaning his/her/its/their own when they refer back to the subject of the sentence.

Which one you use depends on the noun being owned:

• sin for an en-word singular
• sitt for an ett-word singular
• sina for plural nouns

Here, the owned noun is täcke, and täcke is an ett-word:

• ett täcke
• therefore: sitt täcke

So sitt matches täcke, not barnet.

It means the blanket belongs to the subject, the child.

So:

• Barnet vill ha sitt täcke... = the child wants its own blanket
• Barnet vill ha hans täcke... = the child wants his blanket, someone else’s
• Barnet vill ha hennes täcke... = the child wants her blanket, someone else’s

This is a very important Swedish distinction. Sitt shows that the blanket belongs to the child mentioned as the subject.

Because after a possessive word like min, din, sin, sitt, vår, etc., Swedish usually uses the noun in the indefinite form.

So you say:

• mitt hus = my house
• sin bok = his/her own book
• sitt täcke = its own blanket

Not:

• mitt huset
• sin boken
• sitt täcket

So even though English says its blanket, Swedish uses sitt täcke, with the noun in the basic form.

This is a great question, because täcke is an ett-word, so you might expect blått.

Normally, in an indefinite phrase, you do get:

• ett blått täcke

But after a possessive like sitt, adjectives usually take the weak/definite-type form. With blå, that form is commonly just blå.

So:

• ett blått täcke = a blue blanket
• sitt blå täcke = its own blue blanket

A clearer example with another adjective is:

• ett litet täcke
• sitt lilla täcke

So the adjective form changes because of the possessive structure.

Not quite. Blå is a little tricky because some of its forms look the same.

Common forms are:

• en blå bil
• ett blått täcke
• den blå bilen
• det blå täcket
• de blå bilarna

After possessives, you also often get the form blå:

• mitt blå hus
• sitt blå täcke

So in this sentence, blå is correct.

Both are possible in Swedish, but they mean different things.

• på sängen = on the bed
• i sängen = in bed / in the bed

So this sentence specifically says the child wants the blanket on the bed, not necessarily that the child is already lying in bed.

If you changed it to i sängen, the focus would sound more like being in bed.

Sängen is the definite form: the bed.

• en säng = a bed
• sängen = the bed

Here, it refers to a specific bed, so Swedish uses the definite form sängen.

The sentence is following normal Swedish word order:

Barnet / vill ha / sitt blå täcke / på sängen / varje natt

That is:

• subject
• verb
• object
• place
• time

A very common Swedish pattern is:

subject + verb + object + place + time

So på sängen comes before varje natt because place often comes before time.

Because varje is followed by the singular form in Swedish.

So you say:

• varje dag = every day
• varje vecka = every week
• varje natt = every night

Even though the meaning is repeated over many nights, Swedish still uses the singular after varje.

Not in the same way. Barnets is the genitive form, meaning the child’s.

For example:

• Barnets täcke är blått. = The child’s blanket is blue.

But in your sentence, Swedish prefers the reflexive possessive because the blanket belongs to the subject:

• Barnet vill ha sitt blå täcke...

That is more natural than using a genitive structure here.

Not directly. The important thing is that sitt agrees with the thing possessed, not the possessor.

Here:

• possessor = barnet
• possessed thing = täcke

Because täcke is an ett-word, you use sitt.

A useful comparison:

• Barnet vill ha sin bok.
  because bok is an en-word
• Barnet vill ha sitt täcke.
  because täcke is an ett-word
• Barnet vill ha sina leksaker.
  because leksaker is plural

So always look at the noun after sin/sitt/sina.