O juro aumentou.

In Portuguese, nouns often take an article where English might not use one.

Here, o is the masculine singular definite article, meaning the. So o juro is the interest or the interest rate in a general/contextual sense.

In economic or financial language, Portuguese very naturally uses the article:

• O juro subiu.
• O juro desceu.

English often drops the article in similar headlines, but Portuguese usually keeps it.

Because juro is a masculine noun in Portuguese, so it takes o in the singular:

• o juro
• os juros

This is something you generally just have to learn with the noun. There is no special reason visible in this sentence beyond normal noun gender.

Good question. Both forms exist, but they are used a bit differently.

• juro can refer to interest or the interest rate as a concept, especially in more formal or economic language.
• juros is very common when talking about interest charges/payments in practice.

For example:

• A taxa de juro aumentou. = The interest rate increased.
• Os juros do empréstimo são altos. = The loan interest charges are high.

So O juro aumentou is possible and natural, especially in a general/economic sense, but in many everyday situations you may also hear:

• Os juros aumentaram.

Aumentou is the pretérito perfeito do indicativo, which is usually called the simple past or preterite in English-based explanations.

It comes from the verb aumentar = to increase.

So:

• aumentou = increased / went up

In this sentence, it presents the increase as a completed event.

Because Portuguese verb forms do not always show the subject by themselves in the way English does.

Aumentou can mean:

• he increased
• she increased
• it increased
• you increased (formal você)

You know which one it is from the subject or context. Here the subject is o juro, so the meaning is the interest increased.

The infinitive is aumentar.

A few useful forms:

• aumentar = to increase
• aumento = I increase
• aumenta = he/she/it increases
• aumentou = he/she/it increased
• aumentaram = they increased

Here it is used intransitively.

That means the subject itself undergoes the change:

• O juro aumentou. = The interest increased.

But aumentar can also be used transitively:

• O banco aumentou os juros. = The bank increased the interest rates.

So the verb can work both ways depending on the sentence.

Yes, absolutely.

Os juros aumentaram is very common and often sounds very natural when talking about borrowing costs, bank rates, or interest payments in general.

The difference is roughly:

• O juro aumentou = interest / the interest rate increased
• Os juros aumentaram = the interest charges / interest rates increased

In real life, context decides which one sounds better.

Yes. A taxa de juro aumentou is more explicit and often clearer, because it directly says the interest rate increased.

Compare:

• O juro aumentou. = shorter, more condensed
• A taxa de juro aumentou. = more precise

In news, economics, and formal speech, both are possible. If you want to avoid ambiguity as a learner, a taxa de juro is often a very safe choice.

Because o juro is the subject, and the normal word order in Portuguese is, as in English:

subject + verb

So:

• O juro aumentou.

You can change the order in some contexts for style or emphasis, but the basic pattern is the same as English here.

Yes, you can.

Aumentou o juro is grammatically correct, but it sounds more marked, more like a headline, or more focused on the event itself.

Compare:

• O juro aumentou. = neutral statement
• Aumentou o juro. = the increase is foregrounded

Both are possible, but the original sentence is the more neutral learning model.

In European Portuguese, juro is pronounced approximately ZHOO-roo, but with Portuguese sounds:

• j sounds like the s in measure
• u is like oo
• the r between vowels is a light tap, similar to a quick Spanish r

A rough guide:

• juro → ZHOO-ru

The stress is on the first syllable:

• JU-ro

Roughly, aumentou sounds like ow-men-TOH, with the stress on the last syllable.

A few points:

• au sounds like ow
• the en part is nasal in Portuguese
• the final ou in European Portuguese is usually a clear oh sound

So a rough learner-friendly approximation is:

• aw-men-TOH

A rough pronunciation guide is:

o ZHOO-ru aw-men-TOH

A more natural European Portuguese flow may reduce some unstressed vowels, so it can sound more compact than the spelling suggests.

The main stress points are:

• JU in juro
• TOU in aumentou

Yes, it is natural, especially in formal, economic, or news-style language.

That said, depending on context, speakers in Portugal might also say:

• Os juros aumentaram.
• A taxa de juro aumentou.

So the sentence is correct and natural, but not the only common way to express the idea.

No, not in this sentence.

Portuguese juro can also be the first-person singular of the verb jurar:

• Eu juro. = I swear.

But here, because of the article o, it must be the noun:

• o juro = the interest

So the grammar makes the meaning clear.

It would be:

• O juro aumenta. = The interest increases / is increasing

But be careful: in modern European Portuguese, if you want to say something is happening right now, a very common structure is:

• O juro está a aumentar. = The interest is increasing

So:

• aumenta = present / general present
• está a aumentar = is increasing right now
• aumentou = increased

Yes, two things are especially worth noticing:

1. The article Portuguese uses o where English may simply say interest increased in a headline style.

2. The noun choice Portuguese may use juro, juros, or taxa de juro depending on whether the speaker means the concept, the rates, or the actual interest charges.

So even though the sentence is short, it reflects some very typical Portuguese patterns.