A criança segura a mão da mãe na calçada antes de atravessar a rua.

In Portuguese, it is very common to use the definite article before nouns, even when English would often leave it out.

• A criança = the child
• criança by itself would sound more general, like child or a child depending on context

So A criança segura... is the natural way to say The child holds... in this sentence.

Here, segura comes from the verb segurar, which means to hold or to keep hold of.

So:

• A criança segura a mão da mãe = The child holds the mother’s hand

Be careful: segura can also be an adjective meaning safe or secure, but in this sentence it is clearly a verb.

Segura is the simple present tense:

• (ela) segura = she holds / is holding

Portuguese often uses the simple present where English might use either:

• The child holds the mother’s hand
• The child is holding the mother’s hand

If you said segurando, you would normally need another verb:

• A criança está segurando a mão da mãe = The child is holding the mother’s hand

Both can work, but segura is very natural.

Yes, criança is grammatically feminine, so it takes a:

• a criança
• a criança pequena
• a criança está...

But this does not necessarily mean the child is a girl. Criança is a feminine noun that can refer to any child, regardless of biological sex.

This is an important difference between grammatical gender and real-life gender.

Portuguese often prefers a structure like:

• a mão da mãe = the mother’s hand

instead of:

• sua mão = her hand

This is especially common when it helps avoid ambiguity. Sua mão could mean:

• her hand
• your hand
• his hand
• their hand

depending on context and region.

So a mão da mãe is clearer and very natural.

Da is a contraction of:

• de + a = da

So:

• da mãe literally means of the mother
• natural English: the mother’s

Examples:

• a bolsa da mulher = the woman’s bag
• a mão da mãe = the mother’s hand

This de + noun structure is one of the main ways Portuguese expresses possession.

Portuguese uses definite articles much more often than English.

So it is normal to say:

• a mão = the hand
• a rua = the street
• a mãe = the mother

Even where English might say hold his mother’s hand without an article before mother’s hand, Portuguese usually keeps the article:

• segura a mão da mãe

Likewise:

• atravessar a rua = to cross the street

This is just standard Portuguese usage.

Na is a contraction of:

• em + a = na

So:

• na calçada = on the sidewalk / on the pavement

Calçada in Brazilian Portuguese usually means sidewalk.
The phrase tells us where the child is.

Examples of the same pattern:

• na escola = at/in the school
• na rua = in/on the street
• na casa = in the house / at home

It describes the overall situation: the child is holding the mother’s hand on the sidewalk.

Technically, the phrase comes after da mãe, so an English speaker might briefly wonder whether it attaches to mãe, but in normal interpretation it modifies the action or the scene, not the noun mãe.

So the meaning is:

• The child holds the mother’s hand on the sidewalk...

not

• the hand of the mother who is on the sidewalk as some special contrast

Context makes the intended meaning clear.

After antes when talking about before doing something, Portuguese uses de + infinitive.

So:

• antes de atravessar = before crossing
• antes de sair = before leaving
• antes de comer = before eating

This is a very common structure and worth memorizing:

• antes de + infinitive

Because after antes de, Portuguese normally uses the infinitive form of the verb.

So:

• antes de atravessar a rua = before crossing the street

The infinitive is the dictionary form:

• atravessar = to cross

This is similar to English before crossing or before to cross, except English does not use to there, while Portuguese uses de before the infinitive.

Yes.

• atravessar = to cross
• a rua = the street

So:

• atravessar a rua = to cross the street

This is the normal way to say it in Portuguese. You do not need a preposition like across here.

The sentence is actually fairly close to English word order:

• A criança = subject
• segura = verb
• a mão da mãe = object
• na calçada = location
• antes de atravessar a rua = time / circumstance

Portuguese often allows flexibility in word order, but this sentence uses a very natural, neutral order.

A rough structure is:

• The child
• holds
• the mother’s hand
• on the sidewalk
• before crossing the street

So while some details differ, the overall order is quite straightforward.

Yes, that is grammatical and understandable:

• A criança segura a mão de sua mãe

It means essentially the same thing. But a mão da mãe is often more direct and natural in everyday Portuguese.

Also, sua can be ambiguous, so many speakers prefer clearer alternatives such as:

• da mãe
• dela
• da sua mãe in some contexts

So your version is possible, but the original is very idiomatic.

The original sentence is already natural. In speech, a Brazilian speaker might say it with the same wording.

Possible spoken alternatives include:

• A criança segura na mão da mãe na calçada antes de atravessar a rua.
• A criança vai segurando a mão da mãe... depending on context

But the given sentence is perfectly good standard Portuguese.

One small note: in colloquial speech, some speakers say segurar na mão as well as segurar a mão. Both are heard, though segurar a mão is very straightforward and standard here.

A few useful points:

• criança: the ç sounds like s
  • roughly: kree-AHN-sa
• segura: the g before u is a hard g
  • roughly: seh-GOO-ra
• mão: nasal sound at the end
  • roughly like mown with nasalization
• mãe: also nasal
  • roughly my but nasal
• calçada: the ç again sounds like s
  • roughly kaw-SAH-da
• atravessar: final r in Brazilian Portuguese is often softer than in English, especially in many accents

The nasal vowels in mão and mãe are especially important because they are very characteristic of Portuguese pronunciation.