Aquest matí he llegit una notícia a internet.

Because he llegit is a full verb form: the present perfect in Catalan.

• he = I have
• llegit = past participle of llegir (to read)

So he llegit literally matches English I have read.

Catalan often forms past events with:

• haver (auxiliary verb) + past participle

Here:

• he = 1st person singular of haver
• llegit = participle

Without he, llegit by itself would not work as the main verb here.

In modern Catalan, especially in central varieties, the present perfect is very commonly used for recent past actions, including things that happened earlier today.

So Aquest matí he llegit... is very natural for This morning I read / I’ve read...

English often chooses between:

• I read
• I have read

Catalan often prefers the compound form here:

• he llegit

You may also hear another past form:

• vaig llegir

That is also correct Catalan, but he llegit is especially natural for a time period connected to today, such as aquest matí.

Aquest matí means this morning.

It uses:

• aquest = this (masculine singular)
• matí = morning (a masculine noun in Catalan)

Because matí is masculine singular, the demonstrative must match it:

• aquest matí

Compare:

• aquest llibre = this book
• aquesta notícia = this news item / this piece of news

So it is aquest because matí is masculine.

Catalan often uses time expressions like aquest matí, avui, demà, ahir, etc. directly, without a preposition.

So:

• Aquest matí he llegit... = This morning I read / have read...

That is completely normal. English also does this with this morning, today, tomorrow, and so on.

Una is the feminine singular indefinite article, meaning a or one.

• notícia is a feminine singular noun
• so it takes una

That gives:

• una notícia = a news item / a piece of news / an article

This is a point where Catalan and English differ slightly. English news is usually uncountable, but Catalan notícia is countable.

So Catalan can say:

• una notícia = a news story / a piece of news
• dues notícies = two news items

Because grammatical gender in Catalan is a property of the noun itself, and notícia is feminine.

You can see this in the words that agree with it:

• una notícia
• aquesta notícia
• la notícia

Many nouns ending in -a are feminine, and notícia follows that common pattern.

In this sentence, a internet means on the internet.

Catalan can use different prepositions with internet, depending on meaning and style:

• a internet = on the internet
• per internet = via the internet / over the internet
• sometimes a la xarxa = online / on the web

So he llegit una notícia a internet means the news was read on the internet.

Learners should know that usage can vary somewhat by speaker or region, but a internet is a normal way to express this idea.

Catalan often uses internet without an article in this kind of expression.

So:

• a internet = on the internet

Using an article is much less common here. For a learner, the safest choice in this sentence is simply:

• a internet

It is best to learn it as a set expression.

Yes, but the given order is very natural and neutral.

The sentence is:

• Aquest matí = time
• he llegit = verb
• una notícia = object
• a internet = place/medium

Catalan is flexible with word order, but the original version sounds very standard:

• Aquest matí he llegit una notícia a internet.

Other orders may be possible for emphasis, but they can sound less neutral:

• He llegit una notícia a internet aquest matí.
• Una notícia he llegit aquest matí a internet. ← possible only in special contexts, but not the default

So for everyday use, the original order is a very good model.

The exact pronunciation of ll depends on the variety of Catalan, but here are the main learner-friendly points:

• ll is not normally pronounced like English l
• in many varieties, it sounds like a palatal ly sound
• in some varieties, it can sound closer to y

So llegit may sound roughly like:

• lye-ZHEET or
• ye-ZHEET, depending on accent

Also:

• the stress falls on the last syllable because of the spelling: llegit
• the final -t may be weak or not strongly released in normal speech

The most important thing for a beginner is:

• do not pronounce ll like a plain English l
• and do not stress the first syllable

The infinitive is llegir (to read).

Its past participle is llegit.

This is not wildly irregular, but it is something you need to memorize:

• llegir → llegit

Just as in English you memorize:

• read → read

In Catalan you memorize:

• llegir → llegit

So:

• he llegit = I have read

Yes, that is also correct.

• he llegit = present perfect
• vaig llegir = periphrastic past, a very common Catalan past tense

Both can refer to a past action. In many contexts, both are possible.

Very roughly:

• he llegit often feels connected to the present or to a time frame including today
• vaig llegir is a straightforward past narrative form

With aquest matí, many speakers naturally use he llegit, especially if it is still the same day.

So your original sentence is an excellent, natural choice.

They mainly show where the stress falls.

• matí → stress on the last syllable: ma-TÍ
• notícia → stress on the tí syllable: no-TÍ-ci-a

Accent marks are important in Catalan because they help you pronounce words correctly and can sometimes distinguish between different forms.

For learners, it is a good habit to pay close attention to written accents from the beginning.