A sogra perguntou se a senhora vai ao casamento amanhã.

In Portuguese, it is very common to use the definite article before nouns when talking about a specific person.

So a sogra literally means the mother-in-law.

This is more natural in Portuguese than it is in English. English often says just my mother-in-law, Maria, doctor, etc., while Portuguese frequently includes an article:

• a sogra
• a Maria
• o professor

Here, a sogra is the subject of the sentence.

Perguntou is the preterite form of perguntar.

It is:

• 3rd person singular
• used for a completed action in the past

So A sogra perguntou... means The mother-in-law asked...

This is different from:

• perguntava = was asking / used to ask
• pergunta = asks / is asking

Here, se means if or whether.

It introduces an indirect yes/no question after a verb like perguntar.

So:

• A sogra perguntou se... = The mother-in-law asked if/whether...

This is not the reflexive se found in verbs like chamar-se. In this sentence, it is simply a conjunction meaning if/whether.

A senhora is a formal and respectful way to say you when speaking to or about a woman.

In Brazilian Portuguese:

• você = normal, common you
• a senhora = more polite, formal, or respectful you

It is often used:

• with older people
• in customer service
• in more formal situations
• when showing distance or respect

So this sentence sounds more formal than one with você.

Even though a senhora means you, it uses 3rd person singular verb forms.

So:

• a senhora vai
• not a senhora vais

This is the same pattern as:

• você vai
• ela vai

That is a very important feature of Portuguese: some forms meaning you still use 3rd person grammar.

In Portuguese, the present tense is often used to talk about the near future, especially when there is a time word like amanhã.

So:

• vai ao casamento amanhã can mean is going to the wedding tomorrow or will go to the wedding tomorrow

This is very natural in Brazilian Portuguese.

A more explicitly future version would be:

• irá ao casamento amanhã

But that sounds more formal or literary. In everyday speech, vai is much more common here.

Ao is a contraction of:

• a = to
• o = the

So:

• a + o = ao

Because the verb ir often uses the preposition a when talking about destination, and casamento is a masculine noun usually appearing as o casamento, you get:

• ir a o casamento → ir ao casamento

This kind of contraction is very common in Portuguese:

• a + a = à
• de + o = do
• em + a = na

Because Portuguese normally uses an article in many cases where English may not.

Here, casamento is being treated as a specific event:

• o casamento = the wedding

And after ir a, that becomes:

• ir ao casamento = to go to the wedding

Saying just ir a casamento would sound unnatural in standard Portuguese in this context.

Because Portuguese does not normally invert the subject and verb the way English sometimes does in questions.

English:

• Is she going?
• The mother-in-law asked if she is going.

Portuguese:

• Ela vai?
• A sogra perguntou se ela vai.

So after se, Portuguese keeps the normal statement order:

• a senhora vai
• not something like vai a senhora

That is one of the most important differences from English question structure.

Putting amanhã at the end is a very natural position in Portuguese.

It modifies the idea of vai ao casamento and means tomorrow.

This placement is common and neutral:

• A sogra perguntou se a senhora vai ao casamento amanhã.

Other placements are possible, depending on emphasis:

• A sogra perguntou se amanhã a senhora vai ao casamento.
• A sogra perguntou se a senhora amanhã vai ao casamento.

But the original version sounds the most straightforward and natural in everyday use.

It can mean either, depending on context.

• casamento = wedding as an event
• casamento = marriage as a state or institution

In this sentence, because of ir ao casamento, it clearly means the wedding as an event, since you go to a wedding.

A common Brazilian pronunciation is approximately:

• a senhora → ah sen-YOH-rah

A few useful notes:

• nh in senhora is like the ny sound in canyon
• the stress is on -ho-: se-NHO-ra
• in fast speech, it may sound a bit like a sinhora depending on accent

A rough pronunciation of the whole sentence could be:

a so-GRA per-gun-TOH se a sen-YOH-ra vai aw ka-zah-MEN-too a-man-YAH

That is only an approximation, but it can help with the rhythm.