Eu vou comprar sandálias novas amanhã.

In Brazilian Portuguese, ir + infinitive is one of the most common ways to talk about the future, especially in everyday speech.

• Eu vou comprar = I’m going to buy / I will buy
• Eu comprarei = I will buy

Both are correct, but vou comprar sounds more natural and conversational in most spoken Brazilian Portuguese. The simple future (comprarei) is more formal, more written, or sometimes used for emphasis.

Yes. Portuguese often allows the subject pronoun to be omitted when the verb already makes the subject clear.

So both are natural:

• Eu vou comprar sandálias novas amanhã.
• Vou comprar sandálias novas amanhã.

Including eu can add emphasis, contrast, or clarity, but it is not always necessary.

Portuguese does not always need an article where English might use one.

• comprar sandálias novas = buy new sandals

This sounds completely natural in Portuguese. You could also say:

• vou comprar umas sandálias novas = I’m going to buy some new sandals
• vou comprar as sandálias novas = I’m going to buy the new sandals

Without an article, the phrase is general and very normal in this context.

Because adjectives in Portuguese usually agree with the noun in gender and number.

• sandália = singular feminine
• sandálias = plural feminine
• nova = singular feminine
• novas = plural feminine

So:

• sandália nova
• sandálias novas

This kind of agreement is a very important feature of Portuguese grammar.

In Portuguese, adjectives usually come after the noun, so sandálias novas is the most neutral and common order.

You can also say novas sandálias, but that may sound a little more descriptive, literary, or emphatic depending on context. In everyday speech, sandálias novas is the safest choice.

Amanhã is flexible. The version in your sentence is very natural:

• Eu vou comprar sandálias novas amanhã.

But these are also possible:

• Amanhã eu vou comprar sandálias novas.
• Eu vou amanhã comprar sandálias novas. (possible, but less common)
• Eu vou comprar amanhã sandálias novas. (grammatically possible, but less natural)

In normal conversation, the most common placements are:

• at the beginning: Amanhã...
• at the end: ...amanhã

It can match either one in English, depending on context.

Portuguese vou comprar often covers both ideas:

• a planned future action
• a simple future statement

So in many cases, Portuguese does not make the same distinction English does between I’m going to buy and I will buy.

The lh in Portuguese is a special sound, similar to the lli in words like million for many English speakers, though not exactly identical.

A rough guide:

• san-DÁ-lyas

More specifically:

• san = nasalized a bit depending on accent
• dá = stressed syllable
• lias = the lh makes a soft palatal sound

Also:

• sandálias is stressed on dá
• the written accent in á shows the stressed syllable

Amanhã has two sounds that English speakers often find tricky:

• nh sounds like the ny in canyon
• ã is nasal

A rough pronunciation guide is:

• a-ma-NYÃ

The last syllable is nasal, so it is not a plain ah sound. You let some air resonate through the nose.

Yes, it is completely natural.

A Brazilian might also say:

• Vou comprar sandálias novas amanhã.
• Amanhã vou comprar sandálias novas.
• Amanhã eu vou comprar umas sandálias novas.

But your original sentence is correct and sounds normal.

You could say:

• Eu comprarei sandálias novas amanhã.

This is grammatically correct, but in Brazil it usually sounds more formal, more written, or less conversational than eu vou comprar.

In everyday spoken Brazilian Portuguese, vou comprar is much more common.

Comprar is the infinitive form of the verb, meaning to buy.

In vou comprar, the verb phrase is made of:

• vou = first person singular of ir (to go)
• comprar = infinitive

Together they form a future meaning: I am going to buy / I will buy.

Sandálias is the standard and most direct word for sandals.

Depending on the kind of footwear, you might also hear:

• chinelos = flip-flops / slippers
• sapatos = shoes
• rasteirinhas = flat women’s sandals
• papetes = sporty/open sandals

So sandálias is correct, but the exact word can change depending on style.