Eu vou convidar minha tia para a festa de aniversário.

In Brazilian Portuguese, ir + infinitive is a very common way to talk about the near future or a planned future action.

• vou convidar = I am going to invite
• A more formal/simple future form would be convidarei

Both are correct, but vou convidar sounds much more natural in everyday speech.

You can often omit Eu in Portuguese because the verb form vou already shows that the subject is I.

So both are possible:

• Eu vou convidar minha tia...
• Vou convidar minha tia...

Including Eu can add emphasis, clarity, or contrast.

For example:

• Eu vou convidar minha tia, mas meu irmão não vai.
  = I’m going to invite my aunt, but my brother isn’t.

These forms mean different things.

• vou convidar = I am going to invite / future intention
• estou convidando = I am inviting / action in progress right now, or sometimes a current act of invitation

In your sentence, the speaker is talking about a future plan, so vou convidar is the natural choice.

In Brazilian Portuguese, possessives like meu/minha/seu/nosso can appear:

• with an article: a minha tia
• without an article: minha tia

Both are correct.

So these are both possible:

• Vou convidar minha tia...
• Vou convidar a minha tia...

In Brazil, usage varies by region, style, and personal preference. The version without the article is very common and completely natural.

Because tia is a feminine noun.

Possessives agree with the noun they describe:

• meu tio = my uncle
• minha tia = my aunt

So:

• masculine singular noun → meu
• feminine singular noun → minha

Here, para means to or for, depending on how you translate it naturally.

In this sentence:

• convidar alguém para alguma coisa = to invite someone to something

So:

• convidar minha tia para a festa = invite my aunt to the party

This is a very common pattern in Portuguese.

Yes. In everyday Brazilian Portuguese, para a is very often shortened to pra.

So these mean the same thing:

• para a festa
• pra festa

The full version para a festa is more careful or neutral in writing.
The reduced version pra festa is extremely common in speech.

You may also see:

• para o → pro
• para os → pros
• para as → pras

Because they are different structures.

• a festa uses the definite article a = the party
• minha tia uses a possessive = my aunt

With festa, the article is part of saying the party.
With minha tia, Portuguese may or may not use an article before the possessive, depending on style and region.

So:

• a festa = the party
• (a) minha tia = my aunt

Literally, de aniversário means of birthday, but in natural English we say birthday as an adjective.

So:

• festa de aniversário = birthday party

This de + noun structure is very common in Portuguese:

• bolo de chocolate = chocolate cake
• salada de frutas = fruit salad
• festa de aniversário = birthday party

Yes, depending on the context.

• para a festa de aniversário = to the birthday party
  This usually refers to a specific party already known in context.
• para festa de aniversário is less natural in this sentence unless you are speaking more generally or using a less standard structure.

In most normal cases here, para a festa de aniversário sounds best.

Aniversário most often means birthday, but it can also mean anniversary in the broader sense of a yearly date.

Examples:

• Hoje é meu aniversário. = Today is my birthday.
• aniversário de casamento = wedding anniversary

In festa de aniversário, the default meaning is usually birthday party unless context suggests another kind of anniversary.

The structure is:

• Eu = subject
• vou convidar = future expression / verb phrase
• minha tia = direct object
• para a festa de aniversário = prepositional phrase showing what she is being invited to

So the pattern is:

Subject + ir + infinitive + person + para + event

Example pattern:

• Eu vou convidar meu amigo para o jantar.
  = I’m going to invite my friend to dinner.

Yes, but it sounds more formal, literary, or less conversational.

• Eu vou convidar minha tia... = very natural in everyday Brazilian Portuguese
• Eu convidarei minha tia... = correct, but more formal or emphatic

A native speaker in casual conversation would usually prefer vou convidar.

It is similar, but not exactly the same.

tia is usually pronounced roughly like CHEE-ah or TEE-ah, depending on accent and speech style, but in Brazilian Portuguese the ti before a vowel often has a softened sound in many regions.

A practical approximation for learners is:

• tia ≈ chee-ah

But pronunciation varies somewhat across Brazil. The important thing is that it has two syllables:

• ti-a

Yes. Even though vou convidar is literally closer to am going to invite, in many contexts it simply expresses the future and can be translated as:

• I’m going to invite my aunt
• I will invite my aunt

The best English translation depends on context, but the Portuguese structure itself is very normal for future meaning in general.