O herói protegeu a criança.

They are definite articles, meaning the.

• o herói = the hero
• a criança = the child

In Portuguese, articles usually agree with the noun’s grammatical gender:

• o for masculine singular nouns
• a for feminine singular nouns

So here:

• herói is masculine → o herói
• criança is feminine → a criança

Unlike English, Portuguese uses articles very frequently, so leaving them out often sounds unnatural in a normal sentence.

Usually, yes. Herói is the masculine form, so it normally refers to a male hero.

The feminine form is heroína = heroine / female hero.

So:

• O herói protegeu a criança. = a male hero protected the child.
• A heroína protegeu a criança. = a female hero protected the child.

No. Criança is a grammatically feminine noun, but it can refer to any child, male or female.

So a criança can mean:

• the girl
• the boy
• the child, when the gender is unknown or irrelevant

This is a very important distinction in Portuguese: grammatical gender is not always the same as real-life sex/gender.

Protegeu is the preterite form of the verb proteger (to protect).

Specifically, it is:

• third person singular
• simple past / preterite

So protegeu means:

• he protected
• she protected
• it protected

In this sentence, because the subject is o herói, it means the hero protected.

A quick comparison:

• protege = protects / is protecting, depending on context
• protegeu = protected

The infinitive is proteger = to protect.

Some useful forms:

• proteger = to protect
• protejo = I protect
• protege = he/she protects
• protegeu = he/she protected

So if you want to recognize dictionary forms, look up proteger, not protegeu.

The accent in herói shows where the stress falls.

• herói is stressed on the final part: -rói

So it sounds roughly like:

• eh-ROY

The accent helps signal the correct pronunciation and stress pattern.

In Portuguese, accent marks are not optional decoration; they are part of correct spelling and often affect pronunciation.

The ç is called a cedilla.

It tells you that the c is pronounced like s before a, o, or u.

So:

• ça sounds like sa
• ço sounds like so
• çu sounds like su

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

Without the cedilla, ca would normally sound like ka.

In Brazilian Portuguese, protegeu is approximately:

• pro-te-ZHEW

Notes:

• the g in ge sounds like the s in measure
• the final eu sounds like something close to ew

A rough full pronunciation of the sentence is:

• o eh-ROY pro-te-ZHEW a kree-AHN-sa

That is only an approximation for an English speaker, but it is a useful starting point.

A rough English-friendly approximation is:

• kree-AHN-sa

A few details:

• the cri- is like kree
• the an is nasal in Portuguese, so it is not exactly the same as English ahn
• the final ça sounds like sa

Brazilian Portuguese has nasal vowels, so the middle of criança may take practice.

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

• Subject + Verb + Object

So:

• O herói = subject
• protegeu = verb
• a criança = direct object

This is the same basic order as in English:

• The hero protected the child.

Portuguese can change word order for style or emphasis, but this sentence is straightforward and standard.

Because a criança is the direct object of the verb proteger.

In Portuguese, direct objects normally do not take a preposition.

So:

• O herói protegeu a criança.

This works just like English:

• The hero protected the child.

You simply put the object after the verb.

Grammatically, Portuguese usually prefers the articles here.

• O herói protegeu a criança. = normal, natural
• Herói protegeu criança. = sounds unusual in ordinary speech, and more like a headline, note, or very reduced style

So for normal sentence building, learners should usually keep the articles.

Yes. The verb form protegeu by itself does not tell you whether the subject is male or female.

It can mean:

• he protected
• she protected

You know the gender here because the subject is explicitly stated:

• o herói = masculine

So in this sentence, it is clearly he protected.

Here is the breakdown:

• O — definite article
• herói — noun
• protegeu — verb
• a — definite article
• criança — noun

So the whole sentence is:

• article + noun + verb + article + noun

That is a very common and useful sentence pattern in Portuguese.