Det finns en mörk fläck på soffan, men jag vet inte hur den kom dit.

Det finns is the standard Swedish way to say there is / there are.

• Det = literally it
• finns = exists / is found

So Det finns en mörk fläck på soffan means something like There is a dark stain on the sofa.

This is very common in Swedish when introducing something as existing somewhere.

Examples:

• Det finns en bok på bordet. = There is a book on the table.
• Det finns många människor här. = There are many people here.

Because fläck is an en-word in Swedish: en fläck.

With en-words, an adjective in its basic singular indefinite form does not take -t, so:

• en mörk fläck = a dark stain

Compare:

• en mörk stol = a dark chair
• ett mörkt rum = a dark room

So the adjective changes depending on whether the noun is an en-word or an ett-word.

Because the noun phrase is singular and indefinite: en mörk fläck = a dark stain.

The adjective form mörka is used in other situations, especially:

• plural: mörka fläckar = dark stains
• definite forms: den mörka fläcken = the dark stain

Here, since it is just a dark stain, Swedish uses:

• en mörk fläck

På soffan means on the sofa / on the couch. The noun is in the definite form: soffan = the sofa.

Swedish often uses the definite form where English also uses the:

• på soffan = on the sofa
• i bilen = in the car
• på bordet = on the table

If you said på en soffa, that would mean on a sofa, which sounds less specific.

In Swedish, the definite article is usually attached to the end of the noun as a suffix.

So:

• en soffa = a sofa
• soffan = the sofa

This is very normal in Swedish:

• en bok → boken
• ett hus → huset
• en fläck → fläcken

So soffan already includes the idea of the.

Men means but, and jag vet inte means I don’t know.

So:

• men = but
• jag = I
• vet = know
• inte = not

This is straightforward main-clause word order in Swedish:

• Jag vet inte. = I do not know.

Swedish usually puts inte after the verb in a main clause:

• Jag vet inte
• Han kommer inte
• Vi förstår inte

Because this is an embedded question (an indirect question), not a direct question.

Direct question:

• Hur kom den dit? = How did it get there?

Embedded question after jag vet inte:

• Jag vet inte hur den kom dit. = I don’t know how it got there.

In Swedish, embedded questions use normal statement word order:

• question word + subject + verb

So:

• hur den kom dit not
• hur kom den dit

This is a very important word-order pattern in Swedish.

Because fläck is an en-word, so the pronoun referring back to it is den.

• en fläck → den
• ett bord → det

So:

• en mörk fläck ... hur den kom dit
• ett märke ... hur det kom dit

Even though the whole sentence starts with Det finns, that det is just part of the expression det finns and does not tell you the gender of fläck.

Kom is the past tense of komma = to come.

Here, den kom dit literally means it came/got there. In natural English, this is often translated as how it got there.

Swedish often uses the simple past where English might sometimes use present perfect, depending on context. In this sentence, kom sounds natural because the speaker is talking about how the stain ended up there at some point in the past.

Related forms:

• komma = to come
• kommer = comes / is coming
• kom = came
• kommit = come

This is a very natural Swedish way to express the idea of something ending up somewhere.

Literally:

• kom dit = came there

But in English, we often say:

• got there
• ended up there

So in context, hur den kom dit means how it got there or how it ended up there, not necessarily that the stain literally moved by itself.

Swedish often uses komma in this kind of broader sense.

This is a very common learner question.

• där = there (location, being in a place)
• dit = there (direction, movement to a place)

So:

• Den är där. = It is there.
• Den kom dit. = It came/got there.

Because the sentence talks about how the stain arrived at that place, Swedish uses dit, not där.

A useful way to remember it:

• där = there
• hit/dit = to here / to there

In a main clause, Swedish usually places inte after the finite verb.

So:

• Jag vet inte
• Han är inte här
• Vi kommer inte idag

Here, vet is the finite verb, so inte follows it:

• jag vet inte

This is one of the core word-order rules in Swedish.

Yes, absolutely.

• Jag vet inte hur den kom dit = I don’t know how it got there.
• Jag vet inte hur fläcken kom dit = I don’t know how the stain got there.

Using den sounds natural because fläck has just been mentioned, so the pronoun avoids repetition. Repeating fläcken is also grammatically correct, but a little less smooth in normal conversation.

A learner would often notice these key points:

1. Det finns = there is / there are
2. en fläck shows that fläck is an en-word
3. mörk is the adjective form for a singular indefinite en-word
4. soffan is a definite noun: the sofa
5. jag vet inte shows normal main-clause placement of inte
6. hur den kom dit is an embedded question, so the word order is not inverted
7. den refers back to fläck
8. dit is used because the idea is movement to a place, not location in a place

So it is a very useful sentence because it contains several common Swedish patterns at once.