A expedição começou no centro de distribuição.

Expedição is a feminine singular noun, so the definite article is a.

• a expedição = the expedition / the dispatch / the shipment process
• o would be wrong because o is the masculine singular article

Also, Portuguese uses definite articles more often than English does. In a normal sentence like this, A expedição sounds natural because it refers to a specific expedition or dispatch. Leaving the article out would usually sound incomplete here.

Sometimes yes, but not always.

This is a useful false-friend warning:

• In some contexts, expedição really does mean an expedition, like a scientific or military journey.
• But in logistics, shipping, and warehousing, expedição often means dispatch, shipment, or the sending out of goods.

So in this sentence, the word is probably being used in the logistics sense, not in the adventure/journey sense.

Começou is the preterite of começar, in the 3rd person singular.

That means it expresses a completed past event:

• começa = starts / is starting
• começava = was starting / used to start
• começou = started

Here, it tells you that the start of the expedition/dispatch happened at a definite point in the past.

The ç is called a cedilla.

Its job is to make the c sound like s before a, o, or u.

So:

• ca, co, cu normally sound like k
• ça, ço, çu sound like s

That is why começou is pronounced with an s sound in the last part, not a k sound.

This happens because the verb is começar, and when it is conjugated, the spelling keeps that s sound:

• começar
• começo
• começou

No is a contraction of:

• em = in / at
• o = the

So:

• em + o = no

In this sentence, no centro means in the centre or at the centre.

This happens very often in Portuguese:

• no = em + o
• na = em + a
• nos = em + os
• nas = em + as

Because centro is a masculine singular noun, no is the correct form.

Because centro de distribuição is a normal way to name a type of place: a distribution centre.

Here, de distribuição works like a classifier: it tells you what kind of centre it is.

So:

• centro de distribuição = distribution centre
• centro da distribuição would usually mean the centre of the distribution of something specific

In other words, de distribuição is more like part of the name of the facility, while da distribuição would point to a particular distribution process already known from context.

Yes. Portuguese word order is fairly flexible.

The version you have is the most neutral one:

• A expedição começou no centro de distribuição.

But you could also say:

• No centro de distribuição, a expedição começou.

That gives more emphasis to where it started.

So the original sentence is the most straightforward, but other orders are possible depending on emphasis or style.

A careful European Portuguese pronunciation is approximately:

/ɐ ʃpɨðiˈsɐ̃w̃ kumɨˈso nu ˈsẽtɾu dɨ d(ɨ)ʃtɾibu.iˈsɐ̃w̃/

A few useful pronunciation points:

• ex- in expedição often sounds like esh- in European Portuguese
• unstressed e often becomes a very weak sound, sometimes like uh
• -ão is a nasal ending
• começou is stressed on the last syllable: co-me-ÇOU
• centro is stressed on the first syllable: CEN-tro

A rough English-friendly approximation would be:

uh shpuh-dee-SOUNG koo-muh-SOH noo SEN-troo duh dish-tree-boo-ee-SOUNG

That is only approximate, but it can help you get started.

Because in centro de distribuição, the noun distribuição is being used in a general, classifying way, not as a specific thing already identified.

This is very common in Portuguese after de when naming categories or functions:

• centro de distribuição
• cadeia de produção
• sala de espera

If you add the article, the meaning becomes more specific:

• da distribuição = of the distribution, referring to a particular distribution already known in the conversation

So in this sentence, de distribuição is the natural choice.

Yes, depending on style.

Some possible alternatives are:

• teve início — more formal
• iniciou-se — also more formal or written
• arrancou — sometimes used in certain contexts, more like got underway

For example:

• A expedição teve início no centro de distribuição.
• A expedição iniciou-se no centro de distribuição.

But começou is the most neutral and everyday option.