Learn Hardcore Portuguese (Portugal): Ele lê todas as páginas do livro.

The verb is ler (to read). In the present tense:
- ele / ela lê = he / she reads
The ê is a closed mid vowel, similar to the vowel in English “say” but shorter and without a diphthong (closer to [e] in IPA).
The accent also makes it clear that the word is one syllable and prevents it from being confused with other forms in writing (e.g. le doesn’t exist as a form of ler).

So lê is pronounced approximately like “leh” (with a pure, closed e).

How is the verb ler conjugated in the present tense in European Portuguese?

Here is the present indicative of ler (European Portuguese):

eu leio – I read
tu lês – you read (informal singular)
ele / ela lê – he / she reads
você lê – you read (polite / formal singular)
nós lemos – we read
vós ledes – you read (old‑fashioned / very rare in modern speech)
eles / elas leem – they read
vocês leem – you read (plural)

In everyday European Portuguese, you mainly hear: eu leio, tu lês, ele/ela/você lê, nós lemos, vocês/eles/elas leem.

Can I drop the subject pronoun Ele and just say Lê todas as páginas do livro?

Yes, you can drop Ele.

Portuguese is a pro‑drop language: the verb ending already tells you who the subject is. So:

Ele lê todas as páginas do livro.
Lê todas as páginas do livro.

Both are grammatically correct.

However:

You keep Ele if you want to be clear or contrast with someone else (e.g. Ele lê, mas ela não lê. – He reads, but she doesn’t).
In neutral context, it’s common and natural to drop the subject if it’s obvious from context.

Why is it todas as páginas and not just todas páginas?

In Portuguese, when you use todo / toda / todos / todas with a specific noun, you normally need the definite article:

todas as páginas – all the pages
todos os alunos – all the students
toda a casa – the whole house
todo o livro – the whole book

So:

todas páginas is incorrect in standard Portuguese.
You need todas as páginas, with:
- todas (feminine plural)
- as (feminine plural article)
- páginas (feminine plural noun)

All three must agree in gender (feminine) and number (plural).

What’s the difference between todas as páginas do livro and todo o livro / o livro todo?

Nuance:

todas as páginas do livro
Emphasises the individual pages: he reads each page, none skipped.
todo o livro / o livro todo
Means he reads the whole book; in practice this usually also implies all pages, but the focus is on the book as a unit, not on page‑by‑page reading.

Both are natural in European Portuguese:

todo o livro is a bit more “neutral”.
o livro todo is very common in speech.

Your original sentence slightly highlights the idea that no page is left unread.

Why is it do livro and not de o livro?

Do is a contraction of the preposition de + the definite article o:

de
- o → do
de
- a → da
de
- os → dos
de
- as → das

So:

as páginas do livro = the pages of the book
Literally: de o livro → contracted to do livro

In standard Portuguese, this contraction is obligatory in cases like this.
✗ de o livro is not used; it must be ✓ do livro.

How do I know that páginas is feminine, and why do todas and as change?

Páginas is the plural of página, which ends in ‑a, a very common ending for feminine nouns in Portuguese.

Because páginas is feminine plural, all the words that refer to it must agree:

todas – feminine plural of todo / toda / todos / todas
as – feminine plural definite article
páginas – feminine plural noun

If the noun were masculine plural, everything would change to masculine plural:

todos os livros – all the books
(todos
- os
  - livros)

Can I change the word order, like Ele lê o livro todas as páginas or Ele todas as páginas lê?

No, those orders are not natural or correct.

In neutral sentences, Portuguese generally follows Subject – Verb – Object (like English):

Ele (subject)
lê (verb)
todas as páginas do livro (object)

Possible variations:

You can move the object to the front for emphasis:
Todas as páginas do livro ele lê. (stylistic, emphatic)
But you cannot split the object in the way “o livro todas as páginas” does.

So, for everyday speech, keep: Ele lê todas as páginas do livro.

Does lê here mean “is reading” or “reads”? How do I say “He is reading all the pages of the book” in European Portuguese?

The Portuguese present tense (lê) can mean both:

a general/habitual action:
Ele lê muito. – He reads a lot.
an action happening now, depending on context.

To be very clear that it’s happening right now in European Portuguese, you normally use estar a + infinitive:

Ele está a ler todas as páginas do livro.
= He is reading all the pages of the book (right now).

So:

Ele lê todas as páginas do livro.
can be understood as he reads all the pages of the book (habitually or in a described situation),
Ele está a ler todas as páginas do livro.
clearly describes a current ongoing action.

Could Ele lê todas as páginas do livro ever mean “He read all the pages of the book” (past)?

No. As it stands, Ele lê is present tense, so it does not mean “He read”.

For the past, you would normally use:

Ele leu todas as páginas do livro. – He read all the pages of the book.
(preterite / completed action)

So:

lê = present
leu = simple past (preterite)

They are clearly different forms in Portuguese and not usually confused.

How do I pronounce the whole sentence Ele lê todas as páginas do livro in European Portuguese?

Approximate pronunciation (European Portuguese, very roughly in English sounds):

Ele – “EH-leh” (often reduced in fast speech to something like “êl”)
lê – “leh” (closed e)
todas – “TOH-dash” (final s often sounds like sh in many accents)
as – “ash” (again, final s ≈ sh)
páginas – “PAH-zhee-nash”
- á is open (like “a” in father)
- gi before a vowel sounds like “zhee”
do – “doo” (very short)
livro – “LEE-vru” (final o often reduced, not a full English oh)

Spoken more naturally, it flows together, with some reductions in ele and do:
[EH-lê lê TOH-dash ash PAH-zhee-nash du LEE-vru] (very approximate).