A Maria põe um babete no filho antes da sopa, porque ele entorna tudo quando pega no biberão.

In European Portuguese, it is very common to use the definite article before a person's name in ordinary speech.

• A Maria = Maria
• O João = João

So the article does not make it mean the Maria in English. It is just a normal Portuguese pattern, especially in speech and informal writing.

Põe comes from the verb pôr, which means to put, to place, or to put on.

Here:

• A Maria põe um babete no filho = Maria puts a bib on her son

Põe is the 3rd person singular present tense form:

• eu ponho = I put
• tu pões = you put
• ele/ela põe = he/she puts

This verb is irregular, so the forms have to be learned.

Portuguese often leaves out possessives like her, his, or their when the meaning is already clear from context.

So:

• no filho literally = on the son
• but naturally it means on her son, because the subject is A Maria

Portuguese does this much more often than English. If needed, you could say:

• no seu filho = on her son / on his son

But in this sentence, no filho is enough.

Because the idea is putting something onto someone, and Portuguese normally uses em for that idea.

• em + o = no
• so no filho = on the son

With clothes, accessories, or things placed on the body, pôr ... em alguém is very natural:

• pôr um casaco na criança = put a coat on the child
• pôr um chapéu no bebé = put a hat on the baby

A more indirect way would be:

• A Maria põe-lhe um babete = Maria puts a bib on him

But ao filho is not the natural choice here.

Babete means bib.

It is the cloth or plastic thing a baby wears while eating, to stop food from getting on their clothes.

In this sentence:

• um babete = a bib

Because antes is followed by de:

• antes de = before

And de + a sopa contracts to da sopa:

• antes da sopa = before the soup / before soup

So the structure is:

• antes de + noun

Examples:

• antes do jantar = before dinner
• antes da aula = before class

Here, a sopa probably refers to the soup course of the meal.

Here, porque means because.

It introduces the reason:

• A Maria põe um babete no filho antes da sopa, porque ele entorna tudo...
• Maria puts a bib on her son before the soup, because he spills everything...

A useful distinction:

• porque = because
• porquê = the reason / why (as a noun)
• por que = why / for which reason in certain questions and structures

In this sentence, the correct form is porque.

Ele refers to o filho — the son.

So:

• porque ele entorna tudo = because he spills everything

Even though there are other masculine words nearby, like babete and biberão, the meaning makes it clear that ele is the child.

Entornar means to spill, to tip over, or to knock out the contents of something.

So:

• entorna tudo = he spills everything

It suggests that the child makes a mess with whatever he is handling.

Because in European Portuguese, pegar very often goes with the preposition em when it means to take hold of, to grab, or to pick up.

So:

• pegar em o biberão becomes pegar no biberão
• no = em + o

This is very natural in European Portuguese:

• pegar no copo = take hold of the glass
• pegar no livro = pick up the book

Using pegar o biberão is much less natural in European Portuguese for this meaning.

Yes. Biberão is the usual European Portuguese word for a baby bottle.

So:

• pega no biberão = grabs the baby bottle

If you know Brazilian Portuguese, you may have seen:

• mamadeira = baby bottle

That is the usual Brazilian term, while biberão is the standard European Portuguese one.

It sounds like a habit or a usual situation.

• A Maria põe um babete... = Maria puts a bib...
• porque ele entorna tudo... = because he spills everything...

This is the Portuguese present tense used for something that happens regularly or is generally true.

So the idea is:

• she usually puts a bib on him before soup
• because he usually spills everything

Grammatically it is quando = when, but in this context it has the sense of whenever.

• quando pega no biberão = when / whenever he grabs the bottle

Because the whole sentence describes a repeated situation, English often translates it naturally with whenever:

• because he spills everything whenever he grabs the bottle

So both ideas are present, but whenever fits the meaning especially well here.