Learn Hardcore Norwegian: Min niese liker naturfag, mens nevøen min foretrekker samfunnsfag og matte. - My niece likes science, while my nephew prefers social studies and math.

Possessive before the noun (indefinite noun)
- min niese = my niece
- Pattern: min / mi / mitt / mine + indefinite noun
  - min bil (my car)
  - mitt hus (my house)
  - mine bøker (my books)
Possessive after the noun (definite noun)
- nevøen min = my nephew
- Pattern: definite noun + min / mi / mitt / mine
  - bilen min (my car)
  - huset mitt (my house)
  - bøkene mine (my books)

So yes, all of these are grammatically correct:

min niese / niesen min
min nevø / nevøen min

They all mean “my niece / my nephew”. The sentence could also have been:

Min niese liker naturfag, mens min nevø foretrekker samfunnsfag og matte.
Niesen min liker naturfag, mens nevøen min foretrekker samfunnsfag og matte.

The choice is mainly about style and rhythm, not meaning.

Is there a difference in meaning or emphasis between min niese and niesen min?

The basic meaning (my niece) is the same, but there is a subtle difference in feel:

Preposed possessive (min niese)
- Slightly more formal or emphatic.
- Often used more in writing and when you want to stress whose something is:
  - Det er min niese, ikke hennes. – That’s my niece, not hers.
Postposed possessive (niesen min)
- Feels more neutral and conversational, especially with family members.
- Very common in spoken Norwegian:
  - Niesen min bor i Bergen.

In practice, Norwegians switch between the two quite freely. In your sentence, mixing min niese and nevøen min is completely natural and doesn’t imply any special contrast.

Why is nevøen in the definite form, but niese is not? Aren’t we talking about specific people in both cases?

Yes, both refer to specific people, but the grammar of possession forces different noun forms:

With preposed possessive (min niese), the noun appears in the indefinite form (no -en/-et/-a ending).
With postposed possessive (nevøen min), the noun appears in the definite form (nevøen = the nephew).

So:

min niese = literally my niece (indefinite noun)
nevøen min = literally the nephew of mine (definite noun + possessive)

Both are specific; the difference is purely structural, not about how “definite” they are in meaning.

Do I always need to use a possessive with family words like niese and nevø?

In Norwegian you usually must show possession with family members if you mean my/your/his/her, unlike in some other languages.

Natural:

Min niese bor i Oslo. – My niece lives in Oslo.
Nevøen min går på ungdomsskolen. – My nephew goes to lower secondary school.

Unnatural or incomplete if you mean my:

*Niese bor i Oslo. (sounds wrong unless it’s a very strange context)

The main exceptions are:

With mom, dad, grandma etc. in very close, informal speech people may drop the possessive and say:
- Mamma kommer snart. – Mom is coming soon.
- Bestemor er syk. – Grandma is sick.
With names (obviously, no possessive):
- Anna er tanten min. – Anna is my aunt.

But for niese and nevø, you virtually always include something like min, din, hans, hennes, etc.

What exactly does mens mean in this sentence? Is it “while” or “whereas”, and does it affect word order?

Here mens means “while/whereas” in the contrast sense:

Min niese liker naturfag, mens nevøen min foretrekker samfunnsfag og matte.
≈ My niece likes science, whereas my nephew prefers social studies and math.

Key points:

mens is a subordinating conjunction, like fordi (because), selv om (even though).
In this sentence it expresses contrast, not time.
The clause after mens has normal S–V–O word order:
- nevøen min (subject)
- foretrekker (verb)
- samfunnsfag og matte (object)

You can also put the mens-clause first:

Mens nevøen min foretrekker samfunnsfag og matte, liker niesen min naturfag.

Then, in the following main clause, Norwegian applies the V2 rule (verb in second position), so you get:

… liker niesen min naturfag, not *niesen min liker naturfag in that position.

Why is there no article before naturfag, samfunnsfag, and matte?

School subjects in Norwegian are usually treated like uncountable, abstract nouns and are used without an article when you talk about them in general:

Jeg liker naturfag. – I like science (as a subject).
Hun hater matte. – She hates math.
Vi har engelsk i morgen. – We have English tomorrow.

If you add a definite article, you talk about a specific class or course:

Jeg liker ikke naturfaget.
≈ I don’t like the science class / this science course (specific).

So in your sentence, we are talking about the subjects in general, so no article is used.

What do naturfag, samfunnsfag, and matte actually mean, and is matte informal?

Yes, matte is an informal word. Here’s what each term usually means in a Norwegian school context:

naturfag
- Literally “nature subject”.
- Roughly: science, especially general science in school (biology, physics, chemistry, etc., combined).
samfunnsfag
- Literally “society subject”.
- Roughly: social studies – subjects about society, politics, geography, history and civics at the basic and lower secondary levels.
matte
- Short, colloquial form of matematikk (mathematics).
- Very common in speech and informal writing:
  - Jeg liker matte. – I like math.
- In more formal contexts (textbooks, official documents), you will see matematikk:
  - Han studerer matematikk ved universitetet. – He studies mathematics at the university.

So your sentence is quite natural and conversational in tone.

What is the difference between liker and foretrekker?

Both describe positive attitude, but they are not the same:

å like = to like
- Neutral, just says you think something is good/enjoyable.
- Min niese liker naturfag. – My niece likes science.
å foretrekke = to prefer
- Implies a comparison (A is better than B for this person).
- Nevøen min foretrekker samfunnsfag og matte.
  – My nephew prefers social studies and math (over other subjects, e.g. naturfag).

You could also say:

Nevøen min liker samfunnsfag og matte best. – My nephew likes social studies and math best.

That would be similar in meaning to foretrekker, but foretrekker is the direct equivalent of English “prefers”.

Grammar note: present tense:

å like → liker
å foretrekke → foretrekker

Present tense doesn’t change with the subject in Norwegian:

jeg/du/han/vi/de liker – same ending for all persons.

What genders do niese and nevø have, and how does that affect forms like min?

In Bokmål:

nevø is masculine only
- Indefinite: en nevø
- Definite: nevøen
- With possessives:
  - min nevø, nevøen min (my nephew)
niese is typically treated as feminine, but can also be treated as common gender (masculine-like). So you’ll see two parallel systems:
Feminine style:
- ei niese (indefinite)
- niesa (definite)
- mi niese, niesa mi (my niece)
Common-gender style (very common in Bokmål):
- en niese (indefinite)
- niesen (definite)
- min niese, niesen min

In your sentence, min niese uses the common-gender pattern, which is completely standard Bokmål.

How do you pronounce nevø, niese, samfunnsfag, and matte?

Approximate pronunciations (using simple English-like hints, not exact IPA):

nevø
- Roughly: neh-VUH (with lips rounded on the last vowel)
- The ø sound is like German ö in schön, or French eu in peur.
niese
- Roughly: nee-EH-seh
- Three syllables: ni-e-se, stress on the second syllable: ni-E-se.
samfunnsfag
- Roughly: SAHM-foons-fahg
- Stress on the first syllable: SAM-funns-fag.
- The g at the end of fag is usually pronounced, but not very strongly.
matte
- Roughly: MAHT-teh
- Short a, double t means the t is long and the vowel is short: mat-te (two clear syllables, stress on mat).

If you want IPA-like forms as a reference (for standard Eastern Norwegian):

nevø [neˈvøː]
niese [niˈeːsə]
samfunnsfag [ˈsɑm.fʉns.fɑːg]
matte [ˈmɑtːə]

Can I swap the order of the clauses, like starting with the nephew, and does anything change in the grammar?

Yes, you can absolutely start with the nephew’s clause. Two natural variants:

Keep basic order, same conjunction:
- Nevøen min foretrekker samfunnsfag og matte, mens niesen min liker naturfag.
Put the mens-clause first:
- Mens nevøen min foretrekker samfunnsfag og matte, liker niesen min naturfag.

Notice in version 2:

After the initial mens-clause, the verb comes before the subject in the next main clause:
- … liker niesen min naturfag, not *… niesen min liker naturfag.
This is the V2 rule for Norwegian main clauses: the finite verb is normally in second position.

All these versions are grammatical and natural; they just differ slightly in what you mention first and in rhythm.