Jeg kan ikke vente evigt.

In a normal Danish main clause, the finite verb usually comes in second position. That is the V2 rule.

So the order is:

• Jeg = subject
• kan = finite verb
• ikke = negation
• vente evigt = rest of the sentence

That gives:

Jeg kan ikke vente evigt.

Putting ikke before kan would sound wrong in a normal main clause.

Because kan is a modal verb, and in Danish modal verbs are followed by the infinitive without any extra word like English to.

Examples:

• Jeg kan vente. = I can wait.
• Jeg vil vente. = I want to / will wait.
• Jeg skal vente. = I have to / must wait.

So:

• kan = can
• vente = wait

No separate to is needed.

In a main clause, ikke usually comes after the finite verb and often before the infinitive or other parts of the sentence.

So:

• Jeg kan ikke vente.
• Han kommer ikke i dag.
• Vi er ikke klar.

That is one of the most important word-order patterns in Danish.

A useful basic rule is:

subject + finite verb + ikke + rest

In this sentence:

• Jeg = subject
• kan = finite verb
• ikke = not
• vente evigt = rest

Because vente is the infinitive form, and after a modal verb like kan, Danish uses the infinitive.

Compare:

• Jeg venter. = I am waiting / I wait.
  Here venter is finite.

• Jeg kan vente. = I can wait.
  Here vente is infinitive after kan.

So in your sentence:

• kan is the finite verb
• vente stays in the infinitive

Jeg is the Danish subject pronoun meaning I.

Some common Danish subject pronouns are:

• jeg = I
• du = you
• han = he
• hun = she
• vi = we
• I = you plural
• de = they

So Jeg kan ikke vente evigt starts with I.

Evigt means forever or eternally here, and it functions adverbially: it tells you how long the waiting lasts.

It comes from the adjective evig, meaning eternal.

In Danish, the -t form is often used adverbially or as the neuter form of an adjective. In this sentence, evigt works like an adverb:

• en evig ventetid = an eternal waiting time
• vente evigt = wait forever

So evigt is the correct form here.

Yes, but it is not exactly the same.

• Jeg kan ikke vente evigt = I can’t wait forever.
  This suggests a limit, inability, or impatience.

• Jeg venter ikke evigt = I’m not waiting forever.
  This sounds more like a decision or refusal.

So both are possible, but the nuance is different. The version with kan is very natural if you mean that your patience has a limit.

Good question. Danish often uses vente på when you are waiting for someone or something:

• Jeg venter på bussen. = I’m waiting for the bus.
• Hun venter på sin ven. = She is waiting for her friend.

But when there is no expressed object, or when the focus is on the act of waiting itself, vente can appear without på:

• Jeg kan ikke vente længere.
• Vi måtte vente længe.
• Hun kunne ikke vente evigt.

So in Jeg kan ikke vente evigt, there is no specific object after vente, so på is not needed.

In a yes/no question, Danish usually puts the finite verb before the subject:

• Kan jeg ikke vente evigt?

That literally matches Can’t I wait forever? or Can I not wait forever?, depending on context.

Notice that kan moves in front of jeg:

• statement: Jeg kan ikke vente evigt.
• question: Kan jeg ikke vente evigt?

In a subordinate clause, ikke usually comes before the finite verb.

Main clause:

• Jeg kan ikke vente evigt.

Subordinate clause:

• ... fordi jeg ikke kan vente evigt. = ... because I can’t wait forever.

This is a major difference between Danish main clauses and subordinate clauses:

• main clause: verb + ikke
• subordinate clause: ikke + verb

That is something English speakers often need to practice.

Pronunciation varies a bit by region and speaking style, but here are some useful approximations:

• jeg often sounds roughly like yai or ya
• kan sounds roughly like kan with a short vowel
• ikke often sounds like igge
• vente sounds roughly like ven-de
• evigt sounds roughly like ai-vit or ej-vit, depending on accent

A very rough learner-friendly approximation could be:

yai kan igge ven-de ai-vit

A few important notes:

• jeg is rarely pronounced exactly the way it is spelled
• ikke often loses a clear k sound in normal speech
• Danish pronunciation is generally much softer and less fully pronounced than spelling suggests

So it is normal if the spoken sentence sounds much more compressed than the written form.

Very often, yes. Kan ikke is the normal direct equivalent of cannot / can’t.

Examples:

• Jeg kan ikke komme. = I can’t come.
• Han kan ikke svømme. = He can’t swim.
• Vi kan ikke vente evigt. = We can’t wait forever.

But sometimes English can’t expresses something slightly different, like refusal or impossibility in context, and Danish might use a different structure depending on meaning. In your sentence, though, kan ikke is completely natural.

Sometimes, but not always with exactly the same feel.

• evigt often means forever in a straightforward way
• for evigt also means forever, but it can sound a bit more emphatic or permanent

With vente, evigt is very natural:

• Jeg kan ikke vente evigt.

You may also hear:

• Jeg kan ikke vente for evigt.

That is also understandable and natural in many contexts, but evigt alone is very common here.

A simple breakdown is:

• Jeg = subject
• kan = finite modal verb
• ikke = negation
• vente = infinitive
• evigt = adverb of time/duration

So the overall pattern is:

subject + modal verb + negation + infinitive + adverb

This is a very useful pattern to learn, because you can build many Danish sentences from it:

• Jeg kan ikke forstå det. = I can’t understand it.
• Hun vil ikke komme i morgen. = She doesn’t want to come tomorrow.
• Vi skal ikke blive her længe. = We mustn’t stay here long.