Synsvinklen ændrer sig efter kapitlet.

Because synsvinklen is the definite singular form of synsvinkel.

• en synsvinkel = a point of view / a perspective
• synsvinklen = the point of view / the perspective

Danish usually adds the definite article to the end of the noun instead of putting a separate word in front, as English does.

This is a very common pattern in Danish.

The base noun is synsvinkel, and nouns ending in -el often drop the unstressed e when endings are added:

• vinkel → vinklen
• cykel → cyklen
• synsvinkel → synsvinklen

So synsvinklen is the normal standard form.

Because ændrer is in the present tense.

The infinitive is at ændre = to change.
In Danish, the present tense is usually formed by adding -r:

• at ændre = to change
• ændrer = changes / is changing

So Synsvinklen ændrer sig means The point of view changes.

Because Danish often uses the reflexive form ændre sig when something changes by itself or undergoes a change.

Compare:

• Jeg ændrer planen = I change the plan
  → here the verb affects an object
• Planen ændrer sig = The plan changes
  → here the subject itself changes

So ændrer sig is very natural here. English usually does not need itself in the same way, but Danish often does.

Sig is the reflexive pronoun used for third person in Danish.

It can refer back to:

• han = he
• hun = she
• den/det = it
• de = they

In this sentence, sig refers back to synsvinklen. So the idea is that the point of view changes itself / changes.

In natural English, you would normally just say changes, but Danish grammar still uses sig.

Because kapitel is a neuter noun.

• et kapitel = a chapter
• kapitlet = the chapter

So the ending -et shows definite singular neuter.

This is different from common-gender nouns, which usually take -en in the definite singular.

Efter most often means after. So taken literally, efter kapitlet means after the chapter or following the chapter.

However, depending on the meaning you were given, it may be functioning in a broader contextual way. In Danish, prepositions can shift meaning depending on context, and efter can sometimes suggest something like according to or depending on, especially in related expressions such as alt efter.

So the important learner point is:

• the basic meaning of efter is after
• the exact English translation depends on context

Because Danish main clauses usually follow the V2 rule: the finite verb comes in the second position.

Here the structure is:

• Synsvinklen = subject
• ændrer = finite verb
• sig = reflexive pronoun
• efter kapitlet = adverbial phrase

So the verb ændrer stays in second position.

If you move another element to the front, the verb still stays second:

• Efter kapitlet ændrer synsvinklen sig.

That is a very important Danish word-order pattern.

It can be rearranged, but the grammar changes in a predictable way because of Danish word order.

For example:

• Synsvinklen ændrer sig efter kapitlet.
• Efter kapitlet ændrer synsvinklen sig.

Both are grammatical, but when efter kapitlet is moved to the front, the verb ændrer still has to stay in second position, so the subject moves after the verb.

This is one of the big differences from English.

Yes, a few:

• synsvinklen has the main stress on the first syllable: SYNs-
• the y sound in syn does not exist in normal English; it is a rounded front vowel
• ændrer begins with æ, which is somewhat similar to the vowel in cat, but not exactly the same
• the second syllable of ændrer is weak and reduced
• kapitlet is also pronounced with a reduced middle vowel, and the rhythm is lighter than an English speaker might expect

A learner does not need perfect pronunciation right away, but it helps to know that Danish often reduces unstressed syllables quite a lot.