Hon följer inte med i kväll; hon är nämligen redan hemma och vill stanna där.

Because följa med is a separable verb expression. In its dictionary form, it is följa med, but in a main clause the finite verb moves to the normal verb position and the particle med stays later in the clause.

So:

• infinitive: att följa med
• main clause: Hon följer inte med

This is similar to separable verbs in some other Germanic languages. A useful comparison:

• Hon vill inte följa med.
• Hon följer inte med.

In the first sentence, följa med stays together because it is an infinitive. In the second, the finite verb följer is separated from med.

In a normal Swedish main clause, the finite verb usually comes early in the sentence, and sentence adverbs like inte, redan, ofta, and so on typically come after that finite verb.

So:

• Hon följer inte med
• Hon är nämligen redan hemma

This is standard main-clause word order.

A very useful contrast is with subordinate clauses, where inte usually comes before the verb:

• main clause: Hon följer inte med
• subordinate clause: ... att hon inte följer med

So the position of inte is strongly tied to clause type.

Historically, yes, the parts are följa + med, but as an expression följa med very often means come along, join, or go with someone.

So in a sentence like this, you should usually learn it as one unit of meaning, not by translating each word separately.

Common uses:

• Vill du följa med? = Do you want to come along?
• Hon följer inte med. = She is not coming along / joining.

Sometimes it can also mean accompany, depending on context.

Yes. Both i kväll and ikväll are used.

They both mean tonight / this evening. The two-word spelling i kväll is very common and makes the original prepositional phrase clearer. The one-word spelling ikväll is also standard and very common in modern Swedish.

So these are both acceptable:

• Hon följer inte med i kväll.
• Hon följer inte med ikväll.

You will see the same variation with some other time expressions too.

Nämligen gives an explanation or justification for what was just said. In natural English, depending on context, it can feel like you see, after all, because, or the reason is that.

In this sentence, it introduces the explanation for why she is not coming along.

It often sounds a bit more explanatory than a plain because clause. It connects back to the previous statement and says, in effect: this is the reason.

That is the normal position for nämligen in Swedish. It usually comes after the finite verb in a main clause, along with other sentence adverbs.

So:

• hon är nämligen redan hemma

Here:

• hon = subject
• är = finite verb
• nämligen = sentence adverb

Starting a clause with nämligen is much less typical in ordinary Swedish. Learners often want to put it first because of English habits, but in Swedish the middle position is usually the natural one.

Redan is usually placed in the normal adverb position, after the finite verb and before many other complements or adverbials. That is why är redan hemma sounds neutral and standard.

So the order is:

• hon är redan hemma

This is the most natural neutral version.

You may sometimes hear hemma redan in speech, but that usually gives a different rhythm or emphasis. For a learner, är redan hemma is the safest standard pattern to use.

Because hemma means at home and describes location, while hem usually expresses movement toward home.

Compare:

• Hon är hemma. = She is at home.
• Hon går hem. = She goes home.

In your sentence, she is already there, so Swedish uses hemma, not hem.

This location-vs-direction distinction is very important in Swedish.

For the same reason as hemma vs hem: Swedish often distinguishes location from direction.

• där = there, in that place
• dit = to there, to that place

Since stanna means stay, it describes remaining in a place, not moving toward one. So:

• vill stanna där = wants to stay there

If there were motion toward the place, dit would be more likely:

• Hon vill gå dit. = She wants to go there.

Because the sentence contains two independent clauses, and each clause normally needs its own subject in Swedish.

So you have:

• Hon följer inte med i kväll
• hon är nämligen redan hemma och vill stanna där

Even though it is the same person, Swedish does not normally drop the subject here. Repeating hon is completely natural and expected.

No, it is not necessary, but it is perfectly natural. The semicolon links two closely related independent clauses.

You could also write:

• Hon följer inte med i kväll. Hon är nämligen redan hemma och vill stanna där.

That would also be correct.

The semicolon simply shows that the two clauses are very closely connected in meaning. It is a style choice, not a grammar requirement.

Swedish very often uses the present tense for planned, expected, or near-future events, especially when a time expression makes the timing clear.

So:

• Hon följer inte med i kväll

literally uses present tense, but it refers naturally to what will happen tonight.

This is very common in Swedish, and English does something similar in some cases too:

• She is not coming tonight
• The train leaves tomorrow

So there is nothing strange about the tense here. The time phrase i kväll makes the future meaning clear.