Tjuven bröt sig in genom dörren.

Tjuven is the definite singular form of tjuv (thief).

• en tjuv = a thief
• tjuven = the thief

So the sentence is talking about a specific thief: the thief.

The base form is bryta, which often means to break.

Here are the main forms:

• att bryta = to break
• bryter = breaks / is breaking
• bröt = broke
• brutit = broken

So bröt is the past tense.

In bröt sig in, the word sig is part of the verb expression.

• bryta sig in = to break in
• literally, it looks like break oneself in, but you should learn it as a fixed Swedish expression

This is very common in Swedish: some verbs use a reflexive pronoun even when English does not.

So in this sentence, sig does not mean the thief physically broke himself. It is just part of the expression bryta sig in.

Yes. Bryta sig in is the normal way to say break in in the sense of entering illegally by force.

Examples:

• Tjuven bröt sig in. = The thief broke in.
• Någon försökte bryta sig in i huset. = Someone tried to break into the house.

So it is best to treat bryta sig in as a unit.

Good question. They do different jobs:

• in tells you the result or direction: into / in
• genom dörren tells you the route: through the door

So:

• bröt sig in = broke in
• genom dörren = through the door

Together: broke in through the door.

This is very natural in Swedish.

Because genom means through, which fits the idea of entering by passing through the door.

• genom dörren = through the door
• i dörren would usually mean in/on the door, which is a different idea

So if someone forces entry using the door as the way in, genom dörren is the natural choice.

Dörr means door, and dörren means the door.

• en dörr = a door
• dörren = the door

Like tjuven, this is the definite singular form.

Swedish usually puts the definite article at the end of the noun instead of using a separate word like English the.

Normally, no. For this meaning, standard Swedish uses bryta sig in.

So:

• Tjuven bröt sig in genom dörren. = correct
• Tjuven bröt in genom dörren. = not the normal standard phrasing for broke in through the door

The reflexive sig is part of the idiomatic verb.

This is normal Swedish main-clause word order:

• Tjuven = subject
• bröt = finite verb
• sig in = rest of the verb phrase
• genom dörren = adverbial/prepositional phrase

So the structure is basically:

Subject + finite verb + other sentence parts

Swedish is a V2 language, which means the finite verb usually comes in the second position in main clauses. Here, the subject is first, so the verb comes second.

Almost. Swedish often uses bryta sig in where English might say either:

• break in
• break into

For example:

• Tjuven bröt sig in. = The thief broke in.
• Tjuven bröt sig in i huset. = The thief broke into the house.

In your sentence, genom dörren explains the route, so Swedish does not need i plus a place noun.

Not necessarily.

Tjuven bröt sig in genom dörren means the thief forced entry through the door, but it does not strictly say exactly how. In many contexts, it strongly suggests that the door was forced, damaged, or used as the point of entry.

If you wanted to be more explicit, Swedish could say something like:

• Tjuven bröt upp dörren. = The thief forced the door open.
• Tjuven tog sig in genom dörren. = The thief got in through the door.

So bröt sig in focuses on forced illegal entry, not just the door itself.

A rough guide for an English speaker:

• bröt: the ö is not like normal English o. It is closer to the vowel in British English bird or fur, but with rounded lips.
• dörren: same ö sound, and the rr is pronounced in the Swedish way, which depends somewhat on accent

Very rough approximations:

• bröt ≈ brurt with rounded lips
• dörren ≈ DUR-ren or DERR-en, but with Swedish ö

If you are learning pronunciation, the most important thing here is to notice that ö is its own vowel and should not be pronounced like English o.