Depois deste capítulo, eu quero ler o próximo.

Because depois normally uses the preposition de.

So the structure is:

• depois de = after
• este capítulo = this chapter

When de + este come together, they contract:

• de + este = deste

So:

• depois deste capítulo = after this chapter

You could think of it as the Portuguese equivalent of after this chapter, where Portuguese explicitly keeps the de.

Deste means of this or from this, depending on context. In this sentence, it appears because of the contraction:

• de
  • este = deste

Here is the full set for the masculine singular demonstrative:

• este = this
• esse = that
• aquele = that over there / that one

And with de:

• deste = of/from this
• desse = of/from that
• daquele = of/from that over there

So depois deste capítulo literally looks like after of-this chapter, but naturally it means after this chapter.

This is about demonstratives.

In standard Portuguese:

• este / desta / deste usually refers to something close to the speaker, or something being mentioned right now
• esse / dessa / desse often refers to something closer to the listener, or something already mentioned
• aquele / daquela / daquele refers to something more distant

In real Brazilian Portuguese, many speakers often use esse where grammar books might expect este. So in everyday speech, depois desse capítulo is also very common.

That means:

• depois deste capítulo sounds correct and a bit more careful/formal
• depois desse capítulo would also sound natural in Brazil in many contexts

Not always. Portuguese often drops subject pronouns when the verb already makes the subject clear.

So both are possible:

• Depois deste capítulo, eu quero ler o próximo.
• Depois deste capítulo, quero ler o próximo.

Both mean the same thing.

Why include eu then?

Common reasons:

• for emphasis
• for clarity
• for contrast, as in I want to read the next one

So the eu is optional here, but completely natural.

Quero ler is a very common structure in Portuguese:

• quero = I want
• ler = to read

After verbs like querer, poder, precisar, and gostar de, Portuguese often uses an infinitive.

Examples:

• Quero ler. = I want to read.
• Posso entrar. = I can enter.
• Preciso estudar. = I need to study.

So eu quero ler o próximo simply means I want to read the next one.

Because próximo is an adjective meaning next or near, and here it is being used like a noun.

Literally:

• o próximo capítulo = the next chapter
• o próximo = the next one

Portuguese often does this when the noun is understood from context.

So instead of repeating capítulo, the sentence leaves it out:

• eu quero ler o próximo = I want to read the next one

This is very natural.

Yes, absolutely.

These both work:

• Depois deste capítulo, eu quero ler o próximo.
• Depois deste capítulo, eu quero ler o próximo capítulo.

Difference:

• o próximo sounds smoother and avoids repetition
• o próximo capítulo is more explicit

Since capítulo was already mentioned, Portuguese naturally allows o próximo by itself.

No. Próximo can mean either:

• next
• near / close

The meaning depends on context.

Examples:

• o próximo capítulo = the next chapter
• a próxima semana = next week
• A estação mais próxima = the nearest station

In your sentence, because the topic is chapters in sequence, o próximo clearly means the next one.

The comma separates the introductory phrase from the main clause:

• Depois deste capítulo, = introductory time phrase
• eu quero ler o próximo. = main clause

This comma is very natural in writing. It helps readability.

Without the comma, the sentence is still understandable:

• Depois deste capítulo eu quero ler o próximo.

But the comma is better style in this kind of sentence.

Sometimes yes, but not in exactly the same way in every sentence.

• depois can mean afterwards / later
• depois de means after

Examples:

• Depois, eu leio. = Later / Afterwards, I’ll read.
• Depois do almoço, eu leio. = After lunch, I read / I’ll read.

In your sentence, because depois is followed by deste capítulo, it has the sense of after:

• Depois deste capítulo = After this chapter

Yes, but it sounds more formal or literary.

Compare:

• Depois deste capítulo = natural, common
• Após este capítulo = more formal, more written

Both are correct. In everyday Brazilian Portuguese, depois de is usually the more common choice.

A broad, learner-friendly pronunciation guide would be something like:

• Depois deste capítulo, eu quero ler o próximo.
• deh-POYSS JEHS-chee kah-PEE-too-lo, eh-o KEH-roh lehr oo PRO-see-moh

A few useful notes:

• depois sounds roughly like deh-POYSS
• deste in Brazil often sounds like DES-chee or JES-chee, depending on accent
• capítulo is stressed on pí: ca-PÍ-tu-lo
• próximo is stressed on pró: PRÓ-xi-mo
• In many Brazilian accents, ti and di before i can sound like chee and jee

So learners may hear something close to:

• Depois deshte capítulo, eu quero ler o próximo

depending on the speaker’s accent.

Yes, a little.

These are all natural:

• Depois deste capítulo, eu quero ler o próximo.
• Eu quero ler o próximo depois deste capítulo.
• Depois deste capítulo, quero ler o próximo.

The first version is especially natural because it puts the time context first: after this chapter.

Portuguese word order is somewhat flexible, but the original sentence is very standard and clear.

Gender matters because articles and some adjectives must agree with the noun.

Here:

• capítulo is masculine singular
• so you get deste capítulo
• and o próximo refers back to capítulo, so it is also masculine singular

That is why you see:

• o próximo

If the noun were feminine, it would change:

• a próxima página = the next page
• Depois desta página, eu quero ler a próxima.

So agreement is important even when the noun is omitted.