Learn Hardcore Norwegian: Bøkene kan bli liggende på gulvet hvis ingen feier dem opp. - The books can stay lying on the floor if nobody sweeps them up.

In this sentence we are talking about some specific books that are already known from context (for example, the books that just fell on the floor), so Norwegian uses the definite form:

en bok – a book
bøker – books
bøkene – the books

English uses a separate word the, but Norwegian usually marks definiteness with an ending, so bøkene already includes the meaning the books.

What exactly does kan bli liggende mean, and why not just kan ligge?

Kan bli liggende literally means something like can end up (and remain) lying.

Structure:

kan – can / may (modal verb of possibility)
bli – become / get / end up
liggende – lying (present participle of ligge, “to lie” in the sense of being in a horizontal position)

This combination expresses that:

the books end up in a lying position on the floor
and they stay like that for some time

So it matches English “can end up lying” or “can remain lying”.

If you said bøkene kan ligge på gulvet, it would sound more like the books can lie on the floor (it’s allowed / it’s possible for them to be there), not that they accidentally fall and stay there. Bli liggende carries the nuance of ending up and remaining in that state.

Why do we use liggende after bli, and not ligger?

Liggende is the present participle of ligge, and it behaves more like an adjective here:

bli
- present participle = end up / remain in a state

So:

bli liggende ≈ become lying / end up lying
bli stående (from stå) ≈ end up standing / remain standing
bli sittende (from sitte) ≈ end up sitting / remain sitting

Using ligger would be wrong here:
✗ bli ligger is ungrammatical.

Liggende is needed because after bli you’re not putting another finite verb; you’re describing a resulting state, almost like saying become lying where lying is an adjective-like form.

What is the difference between ligge and just være in this kind of sentence?

Both talk about “being” somewhere, but ligge is more specific:

være – to be (very general)
ligge – to lie / be in a horizontal position
sitte – to sit / be seated
stå – to stand / be upright

Norwegian likes to specify the position of things and people:

Bøkene ligger på gulvet. – The books are (lying) on the floor.
Stolen står i hjørnet. – The chair is (standing) in the corner.
Hun sitter i sofaen. – She is (sitting) on the sofa.

In kan bli liggende, ligge is chosen because books on the floor are in a lying position, not just generically “are.”

What role does kan play here? Could we say Bøkene blir liggende på gulvet hvis ingen feier dem opp instead?

Kan expresses possibility, like can / may:

Bøkene kan bli liggende … – The books can end up remaining on the floor (it’s possible that this happens).

If you say:

Bøkene blir liggende på gulvet hvis ingen feier dem opp.

you sound more certain:
“The books will end up remaining on the floor if no one sweeps them up.”

So:

kan bli liggende – it’s a possible outcome.
blir liggende – this is what will actually happen given that condition.

Why is it på gulvet and not på gulv?

Again this is about definiteness.

et gulv – a floor
gulv – floors (indefinite plural) or “floor” in some bare-noun uses
gulvet – the floor (definite singular)

Here, we’re talking about the floor of the room everyone knows about, so Norwegian uses the definite singular:

på gulvet – on the floor (of this place / here)

Using på gulv would be odd in this context; it sounds like on (some) floors in a very general sense, not a specific, concrete floor.

What exactly does feier dem opp mean? Isn’t feie already “to sweep”?

Yes, feie means to sweep, especially with a broom.

Adding opp makes a particle verb:

feie – to sweep (an area, e.g., the floor)
feie opp noe – to sweep something up (collecting it into a pile / off the floor)

So:

ingen feier dem opp ≈ nobody sweeps them up (picks the books up from the floor using a sweeping motion / cleans them away).

The opp adds the idea of removal / collecting up, similar to English “sweep up” vs just “sweep”.

Why is the word order feier dem opp and not feier opp dem?

With particle verbs (verb + little word like opp, inn, ut, etc.), the normal word order in a main clause with a pronoun object is:

verb + pronoun object + particle

So:

feier dem opp – correct and natural
feier opp dem – possible only if dem is very heavily stressed or contrasted (and even then, it sounds marked).

Compare:

Han tar den opp. – He picks it up.
Vi skriver det ned. – We write it down.

When the object is a full noun phrase, you can place it either before or after the particle, with slightly different emphasis:

feier bøkene opp
feier opp bøkene

But with dem, the pronoun, feier dem opp is the default.

Why is it dem and not de in hvis ingen feier dem opp?

Norwegian distinguishes between subject and object forms of they:

de – subject form (they)
dem – object form (them)

In hvis ingen feier dem opp:

subject: ingen – nobody
verb: feier – sweeps
object: dem – them (the books)

Since "the books" are the object of feier, you must use dem, not de:

✗ hvis ingen feier de opp – incorrect
✓ hvis ingen feier dem opp – correct

Can ingen really stand on its own to mean “nobody”?

Yes. Ingen means no one / nobody, and it can be used:

With a noun:
- ingen person – no person / nobody
- ingen venner – no friends
By itself, as a pronoun:
- Ingen feier dem opp. – Nobody sweeps them up.

In the sentence hvis ingen feier dem opp, ingen is the subject of the clause and means nobody.

Why is the word order hvis ingen feier dem opp and not something like hvis ingen dem feier opp?

In a subordinate clause started by hvis (if), word order is basically:

[subordinate conjunction] + subject + verb + (object) + other elements

So:

hvis – if (subordinating conjunction)
ingen – subject
feier – verb
dem – object
opp – particle

→ hvis ingen feier dem opp

Putting dem before the verb as in hvis ingen dem feier opp breaks normal Norwegian word order and is ungrammatical.

Could you use om instead of hvis here, as in … om ingen feier dem opp? Is there a difference?

You can say:

Bøkene kan bli liggende på gulvet om ingen feier dem opp.

In spoken Norwegian, hvis and om are both often used to mean if, and here they are normally interchangeable.

Nuances (very roughly):

hvis is the most neutral standard word for if in conditional sentences.
om can also mean if / whether in indirect questions:
- Jeg vet ikke om han kommer. – I don’t know if he is coming.

In this conditional sentence, hvis is slightly more typical in writing, but om is also common and acceptable in many varieties of Norwegian.

What tense or time reference does kan bli liggende have? Is it present or future?

Grammatically, kan and blir are in the present tense, but Norwegian often uses the present tense to talk about the future, especially when the context makes the time clear.

Here, the sentence describes a possible future situation:

Bøkene kan bli liggende på gulvet hvis ingen feier dem opp.
≈ The books can end up lying on the floor if nobody sweeps them up (later).

So:

form: present tense
meaning: present or future possibility, depending on context (here, clearly future-oriented)