O navio chegou ao porto.

O is the masculine singular definite article, so it means the.

So:

• o navio = the ship

In Portuguese, articles are used very often, sometimes more often than in English. Here it tells you we are talking about a specific ship, not just any ship.

Yes, navio is a masculine noun, which is why it takes o:

• o navio

Many Portuguese nouns ending in -o are masculine, so that is a useful pattern. But it is only a pattern, not a perfect rule.

Also, grammatical gender here has nothing to do with biological sex. A ship is not male; navio is simply a masculine noun in Portuguese.

Chegou is the 3rd person singular of the verb chegar in the pretérito perfeito.

That means it is the normal simple past form for a completed action:

• eu cheguei = I arrived
• ele/ela chegou = he/she arrived
• o navio chegou = the ship arrived

So in this sentence, chegou agrees with o navio, which is a third-person singular subject.

Because a + o contracts to ao in Portuguese.

Here is the breakdown:

• chegar a = to arrive at / to arrive to
• o porto = the port

So:

• chegar a o porto becomes chegar ao porto

This kind of contraction is very common in Portuguese.

Other examples:

• a + a = à
• de + o = do
• em + o = no

In standard Portuguese, especially in European Portuguese, chegar commonly takes the preposition a to show the destination:

• chegar ao porto
• chegar à estação
• chegar a casa

So chegou ao porto is the normal standard way to say that the ship arrived at the port.

For European Portuguese, chegou ao porto is the standard choice.

A native English speaker often asks this because in some varieties of Portuguese, especially in much Brazilian usage, you may hear chegar em / no. But in Portugal, with chegar, a is the usual and expected preposition for destination.

So:

• chegou ao porto = standard in Portugal

By contrast, no porto is very natural with verbs of location:

• está no porto = it is in the port

So a useful contrast is:

• chegou ao porto = arrived at the port
• está no porto = is at/in the port

Normally, when referring to a specific port, Portuguese uses the definite article:

• o porto
• ao porto

So ao porto is the normal form here.

Without the article, a porto is not the ordinary choice in this basic sentence. There are some fixed expressions where porto appears without the article, such as chegar a bom porto, but that is more idiomatic and does not mean exactly the same thing as this straightforward sentence.

No. Here porto is a common noun meaning port or harbour.

The clue is the lowercase p:

• porto = port, harbour
• Porto = the city of Porto

So this sentence is about a ship arriving at a harbour, not arriving in the city of Porto.

If you meant the city, you would normally write Porto with a capital letter.

A rough European Portuguese pronunciation is:

u nɐ-ˈvi-u shɨ-ˈgho aw ˈpor-tu

A few helpful points:

• O often sounds like u
• navio has the stress on vi
• ch in chegou sounds like English sh
• g in chegou sounds like the g in go
• porto has the stress on the first syllable: POR-to
• the r in porto is usually a tapped r, not a strong English r

If you want to sound more European Portuguese, remember that unstressed vowels are often reduced.

No. This is a very normal, neutral word order in Portuguese:

• O navio = subject
• chegou = verb
• ao porto = destination phrase

So it follows a straightforward subject + verb + complement pattern.

Portuguese can change word order for style or emphasis, but O navio chegou ao porto is the most neutral and natural version for a learner to use.