Meu sogro vai chegar cedo para o jantar.

Sogro means father-in-law.

It refers to your spouse’s father. Related words:

• sogra = mother-in-law
• genro = son-in-law
• nora = daughter-in-law

So meu sogro means my father-in-law.

Because meu has to agree with the noun sogro, which is masculine singular.

Portuguese possessives change for gender and number:

• meu = my, masculine singular
• minha = my, feminine singular
• meus = my, masculine plural
• minhas = my, feminine plural

So:

• meu sogro = my father-in-law
• minha sogra = my mother-in-law

In Brazilian Portuguese, possessives can appear with or without the definite article, depending on style, region, and context.

So both can be natural:

• Meu sogro vai chegar cedo para o jantar.
• O meu sogro vai chegar cedo para o jantar.

In Brazil, using the article before possessives is very common, but leaving it out is also completely normal, especially in straightforward statements like this one.

Vai chegar is the very common ir + infinitive future construction.

Literally, it is something like is going to arrive, but in normal Portuguese it often simply means will arrive.

Structure:

• vai = goes / is going
• chegar = to arrive

So:

• vai chegar = is going to arrive / will arrive

This is one of the most common ways to talk about the future in everyday Brazilian Portuguese.

Yes. Chegará is the simple future form of chegar.

So both are correct:

• Meu sogro vai chegar cedo para o jantar.
• Meu sogro chegará cedo para o jantar.

The difference is mostly style:

• vai chegar sounds more natural in everyday spoken Brazilian Portuguese
• chegará sounds a bit more formal, written, or polished

Cedo is an adverb meaning early.

It does not change form. It stays cedo no matter who the subject is.

Examples:

• Ele chegou cedo. = He arrived early.
• Eles chegaram cedo. = They arrived early.

In your sentence, cedo tells us when the father-in-law will arrive.

Yes, literally it is for the dinner, but in natural English it usually means for dinner or in time for dinner.

Breakdown:

• para = for / to
• o jantar = the dinner

So para o jantar means he will arrive early for dinner, probably early enough to be there before it starts.

Yes. In everyday Brazilian Portuguese, para o is often shortened to pro.

So these mean the same thing:

• Meu sogro vai chegar cedo para o jantar.
• Meu sogro vai chegar cedo pro jantar.

The full form para o is a bit more neutral or careful. The contracted form pro is extremely common in speech.

Similarly:

• para a → pra

Example:

• pra festa = for the party

Here, jantar is a noun, meaning dinner.

You can tell because it comes with the article o:

• o jantar = the dinner

But jantar can also be a verb:

• Vamos jantar. = Let’s have dinner.
• Eles jantam cedo. = They have dinner early.

So Portuguese uses the same word as both:

• jantar = dinner
• jantar = to have dinner

Yes. In Portuguese, the present tense can also be used to talk about the near future, especially when the context makes it clear.

So these are all possible:

• Meu sogro vai chegar cedo para o jantar.
• Meu sogro chega cedo para o jantar.
• Meu sogro chegará cedo para o jantar.

Very roughly:

• vai chegar = most common and conversational
• chega = also natural, often for scheduled or expected future events
• chegará = more formal

The sentence follows a very common Portuguese pattern:

Meu sogro + vai chegar + cedo + para o jantar

That is:

• subject = Meu sogro
• verb phrase = vai chegar
• adverb = cedo
• purpose/time-related phrase = para o jantar

So Portuguese is being pretty similar to English here:

• My father-in-law
  • will arrive
    • early
      • for dinner

Not necessarily. Like English my, Portuguese meu can show a relationship, not ownership.

So meu sogro does not mean you own your father-in-law. It just means my father-in-law, meaning your family relationship to him.

This is the same idea as:

• minha mãe = my mother
• meu amigo = my friend
• meu professor = my teacher