Learn Hardcore Norwegian: Når jeg er for trøtt, kan jeg ikke lese lenger. - When I am too tired, I cannot read anymore.

når is used for:
- General situations / habits:
  - Når jeg er for trøtt, kan jeg ikke lese lenger.
    When I’m too tired, I can’t read anymore (this is something that is generally true).
- Things you expect will happen (future events):
  - Når jeg kommer hjem, ringer jeg deg.
    When I get home, I’ll call you.
hvis is used for:
- Conditional if-clauses (it may or may not happen):
  - Hvis jeg er for trøtt, kan jeg ikke lese lenger.
    If I’m too tired, I can’t read anymore.

In your sentence, når suggests this is a regular or typical situation. Hvis would also be grammatically correct, but it would sound more like a hypothetical condition than a general rule.

What exactly does «for trøtt» mean, and how is it different from just «trøtt» or «veldig trøtt»?

trøtt = tired
- Jeg er trøtt. – I’m tired.
veldig trøtt = very tired (a strong degree, but not necessarily “too much”):
- Jeg er veldig trøtt. – I’m very tired.
for trøtt = too tired (more than is good/acceptable for the situation):
- Jeg er for trøtt til å lese. – I’m too tired to read.

The little word for here means “too” (as in too much), not “for” in the English sense. So for + adjective often means “too [adjective]”:

for dyr – too expensive
for liten – too small
for rask – too fast

Why is it «kan jeg ikke lese lenger» and not «jeg kan ikke lese lenger» or «jeg kan ikke lenger lese»?

The core word order rule in Norwegian main clauses is V2: the finite verb must be in second position.

In your sentence, the first clause Når jeg er for trøtt is a whole subordinate clause. After that comes the main clause:

kan – finite verb
jeg – subject
ikke lese lenger – rest of the clause

So:

Når jeg er for trøtt, kan jeg ikke lese lenger. ✅
(Main clause starts with kan as the second element overall.)

If you start the sentence directly with the subject, you can say:

Jeg kan ikke lese lenger når jeg er for trøtt. ✅
(Now jeg is first and kan is second, still V2.)

Jeg kan ikke lenger lese is also grammatically possible, but it sounds a bit more formal or marked. The most natural everyday options are:

Når jeg er for trøtt, kan jeg ikke lese lenger.
Jeg kan ikke lese lenger når jeg er for trøtt.

Why is it «lese» and not «leser» after «kan»?

In Norwegian, after modal verbs (like kan, vil, må, skal, bør), you use the infinitive form of the main verb, without å:

kan lese – can read
vil spise – want to eat
må sove – must sleep

So:

Jeg leser. – I am reading / I read. (normal present tense)
Jeg kan lese. – I can read. (kan = finite verb, lese = infinitive)

That’s why you say:

… kan jeg ikke lese lenger. ✅
not
… kan jeg ikke leser lenger. ❌

What does «lenger» mean here, and how is it different from «mer»?

In this sentence, lenger is used in a negative structure ikke … lenger, which means:

ikke … lenger = no longer / not anymore

So:

Jeg kan ikke lese lenger.
= I can’t read anymore / I can no longer read.

Difference from mer:

mer = more (quantity/amount):
- Jeg vil lese mer. – I want to read more.
- Jeg har ikke mer tid. – I don’t have more time.
lenger usually relates to time or distance (longer):
- Jeg vil lese lenger. – I want to read longer (for a longer time).
- Jeg kan ikke lese lenger. – I can’t read any longer / anymore.

In negative sentences about continuing something, ikke … lenger is the normal way to say “no longer / not anymore.”

I’ve seen both «lenger» and «lengre». Which one is right here?

In this sentence, the correct form is lenger:

ikke … lenger = no longer, not anymore ✅

The rough rule of thumb:

lengre – comparative of lang (long → longer) in many contexts of distance:
- Denne veien er lengre. – This road is longer.
lenger – adverb, often used for time/distance and very often in ikke … lenger:
- Jeg kan ikke vente lenger. – I can’t wait any longer.
- Vi bor ikke her lenger. – We don’t live here anymore.

Native speakers sometimes mix them up in writing, but ikke … lenger is the standard spelling.

Why is there a comma after «Når jeg er for trøtt»?

In standard written Norwegian (especially Bokmål), you normally put a comma between a subordinate clause and the main clause when the subordinate clause comes first.

Når jeg er for trøtt, kan jeg ikke lese lenger.
- Når jeg er for trøtt = subordinate clause
- kan jeg ikke lese lenger = main clause

So you write:

Når jeg er for trøtt, kan jeg ikke lese lenger. ✅

If you reverse the order, the comma usually disappears:

Jeg kan ikke lese lenger når jeg er for trøtt. ✅ (no comma)

Could I say «Når jeg blir for trøtt» instead of «Når jeg er for trøtt»? What’s the difference?

Yes, you can say both, but there’s a nuance:

Når jeg er for trøtt, kan jeg ikke lese lenger.
Focus: the state of already being too tired.
When I am too tired, I can’t read anymore.
Når jeg blir for trøtt, kan jeg ikke lese lenger.
Focus: the moment of becoming too tired.
When I (get/become) too tired, I can’t read anymore.

In everyday speech, both are natural, and the difference is small. Er is slightly more general/state-like; blir points a bit more to the change/transition.

What is the difference between «trøtt» and «sliten»? Could I say «for sliten» here?

Both can translate as “tired”, but they have different typical uses:

trøtt – sleepy, lacking energy, want to go to bed:
- Jeg er trøtt. – I’m tired/sleepy.
sliten – worn out, exhausted, used up (often physically or mentally from effort):
- Jeg er sliten etter jobb. – I’m worn out after work.

You can say:

Når jeg er for sliten, kan jeg ikke lese lenger.

This would mean more like:

When I am too worn out/exhausted, I can’t read anymore.

So:

for trøtt → too sleepy/tired to continue
for sliten → too exhausted/worn out to continue

Where should «ikke» go with «kan»? Why is it «kan jeg ikke» and not «kan ikke jeg» here?

Basic order in a main clause with a modal verb:

Finite verb (here: kan) – must be in second position.
Subject (here: jeg).
ikke (negation).
Rest of the verb phrase (here: lese lenger).

So:

… kan jeg ikke lese lenger. ✅ (natural order)

You can say «kan ikke jeg …» in some contexts, but then you are usually:

adding emphasis on jeg (contrast with someone else), or
asking a question: Kan ikke jeg lese lenger? – Can’t I read anymore?

In a normal neutral statement, the standard pattern is:

[V2] + subject + ikke + rest
→ kan jeg ikke lese lenger.