He llegit aquest article dues vegades perquè és important.

In Catalan, he is the 1st person singular form of the auxiliary verb haver in the present tense.

So:

• he llegit = I have read
• has llegit = you have read
• ha llegit = he/she has read

This is just a coincidence in spelling. It has nothing to do with the English pronoun he.

Also, the h in Catalan is silent, so he is pronounced more or less like eh.

Catalan often drops subject pronouns when the verb form already shows who the subject is.

Because he already clearly means I have, you normally do not need jo.

So:

• He llegit aquest article... = normal, natural
• Jo he llegit aquest article... = possible, but more emphatic, as if you want to stress I in particular

This works much like Spanish or Italian.

He llegit is the present perfect (also called the perfect tense).

It is formed with:

• haver in the present tense
• • the past participle

So here:

• he = present of haver
• llegit = past participle of llegir (to read)

This is the same basic idea as English I have read.

Because after the auxiliary haver, Catalan uses the past participle, not the infinitive.

So:

• llegir = to read (infinitive)
• llegit = read (past participle)

Compare:

• Vull llegir = I want to read
• He llegit = I have read

For many -ir verbs, the participle ends in -it:

• dormir → dormit
• sentir → sentit
• llegir → llegit

Because article is a masculine singular noun in Catalan.

The demonstrative must agree with the noun:

• aquest = masculine singular
• aquesta = feminine singular
• aquests = masculine plural
• aquestes = feminine plural

So:

• aquest article = this article
• aquesta revista = this magazine

Agreement is very important in Catalan.

Because vegada is a feminine noun, and the number two has masculine and feminine forms in Catalan:

• dos = masculine
• dues = feminine

So:

• dues vegades = two times
• dos llibres = two books

This gender distinction mainly matters with two. Most other numbers do not change for gender.

Yes. That is very natural.

Both mean twice / two times:

• dues vegades = literally two times
• dos cops = also very common, literally two blows/strikes, but idiomatically two times

Why the change?

• vegada is feminine → dues
• cop is masculine → dos

So both are correct:

• He llegit aquest article dues vegades
• He llegit aquest article dos cops

Because perquè means because.

This is an important distinction in Catalan:

• perquè = because
• per què = why / for what
• per que = possible in some other structures, but not the one used here

So in your sentence:

• ...perquè és important = ...because it is important

A learner often confuses perquè and per què, so it is worth memorizing this contrast early.

Because Catalan usually uses ser for an essential quality, characteristic, or classification, and estar for a state or condition.

Here, important is treated as a characteristic of the article, so:

• és important = it is important

Compare:

• És interessant. = It is interesting.
• Està obert. = It is open.
• Està cansat. = He is tired.

So és important is the natural choice.

The sentence is natural as it stands, but Catalan does allow some flexibility in word order.

The most neutral order is:

• He llegit aquest article dues vegades perquè és important.

You may also hear variations like:

• He llegit dues vegades aquest article...
• Aquest article l’he llegit dues vegades...

These alternatives usually change the focus or emphasis, not the basic meaning.

So the original sentence is a good standard model, but it is not the only possible order.

Yes, but the nuance can change depending on the dialect and context.

• He llegit = present perfect
• Vaig llegir = periphrastic past, a very common Catalan past tense

In many everyday situations, both can refer to a past action. But broadly speaking:

• he llegit often connects the action more closely to the present
• vaig llegir sounds more like a completed past event

So:

• He llegit aquest article dues vegades = I have read this article twice
• Vaig llegir aquest article dues vegades = I read this article twice

In real usage, especially across different Catalan-speaking regions, there can be variation.

A rough guide is:

Eh zhuh-JEET ah-KEST ar-TI-kluh DOO-uz buh-GAH-duhs per-KEH ez eem-por-TANT

A few useful pronunciation points:

• h is silent: he sounds like eh
• ll in llegit is a palatal sound; depending on the speaker, it may sound somewhat like ly or like a soft y/j sound
• qu in aquest is pronounced like k
• the written accents in és and perquè show the stressed vowel

Pronunciation varies by dialect, so this is only an approximation, but those features are the main ones to notice.