Learn Hardcore Portuguese (Brazil): O prato está sujo, vou lavar agora. - The plate is dirty, I am going to wash it now.

In Portuguese, o means the (definite article) and um means a / one (indefinite article).
Using o prato suggests a specific plate that both speakers can identify (for example, the plate on the table).
If you said um prato está sujo, it would sound more like a plate is dirty (some plate, not necessarily a specific one already known in the context).

What exactly does prato mean here?

Prato most commonly means plate (the physical object).
It can also mean dish / course in the sense of food (for example, um prato de macarrão = a dish of pasta, prato principal = main course).
In this sentence, from context, it means the plate is dirty.

Why is it está sujo and not é sujo?

Portuguese uses estar for temporary or current states and ser for permanent or inherent characteristics.
Está sujo means is dirty right now (temporary condition).
If you say é sujo, it suggests is dirty by nature / is a dirty person/place/thing in general, which is not what you usually mean about a plate at the moment.

Why is the adjective sujo and not suja?

Adjectives in Portuguese agree in gender and number with the noun they describe.
Prato is a masculine singular noun, so the adjective is sujo (masculine singular).
If the noun were feminine, for example a panela (the pot), you would say a panela está suja.
For plural: os pratos estão sujos, as panelas estão sujas.

Why is está and not estão used here?

Está is the third person singular form of estar, used with singular subjects.
The subject here is o prato (one plate), so you use está.
If it were plural, for example os pratos, you would say os pratos estão sujos.

Why is there no word for it in vou lavar agora?

Portuguese often omits object pronouns when they are obvious from context.
Here, both speakers know vou lavar agora refers to the plate, so a pronoun like o or ele is not necessary.
You could say something like vou lavá-lo agora (I’m going to wash it now – more formal/standard) or in everyday speech vou lavar ele agora, but most of the time Brazilians just omit it when it’s clear.

Why is there no eu before vou lavar?

Portuguese is a pro-drop language: subject pronouns are often dropped because the verb ending already shows who the subject is.
Vou is only used with eu (I), so eu vou lavar and vou lavar both mean I’m going to wash.
Saying eu is optional here and is usually added for emphasis or clarity.

Why is the future expressed as vou lavar and not with the simple future lavarei?

In Brazilian Portuguese, the ir + infinitive form (vou lavar, vai lavar, etc.) is the most common way to express the near or planned future in speech.
The simple future like lavarei exists and is correct but sounds formal, written, or a bit literary in everyday Brazilian speech.
So vou lavar agora is the natural way to say I’m going to wash (it) now / I’ll wash it now.

Does vou lavar mean I’m going to wash or I will wash? Is there a difference?

Vou lavar can cover both meanings: I’m going to wash (planned / near future) and I’ll wash (decision about the future).
Context and intonation usually show whether it’s a plan, a promise, or a spontaneous decision.
In this sentence with agora, it clearly means something like I’ll wash it right now / I’m going to wash it now.

What is the role of agora in this sentence? Can it be left out?

Agora means now and tells us when the action will happen.
If you say just vou lavar, it still means you will wash it, but the timing is less precise.
Adding agora emphasizes that you’re going to do it immediately.
You can also hear variants like agora mesmo (right now) or já (which can also mean “right now / already” depending on context).

Is the comma between O prato está sujo and vou lavar agora correct? Could I use então or porque?

Yes, it’s common in Portuguese to join two short related clauses with a comma, especially in informal writing: O prato está sujo, vou lavar agora.
You can also make the relationship explicit with words like:

O prato está sujo, então vou lavar agora. (The plate is dirty, so I’ll wash it now.)
Vou lavar o prato agora porque está sujo. (I’m going to wash the plate now because it’s dirty.)
The original is a bit informal, but very natural in everyday usage.

How would I say The dishes are dirty, I’m going to wash them now?

You would make both the noun and adjective plural:
Os pratos estão sujos, vou lavar agora.
Again, you can omit them because it’s understood that vou lavar refers to os pratos.
More explicit (and a bit more formal) would be Os pratos estão sujos, vou lavá‑los agora.

How do you pronounce prato, está, sujo, vou, lavar, and agora in Brazilian Portuguese?

Approximate pronunciations (Brazilian accent):

prato ≈ PRAH-too (the r is like a light h in many regions)
está ≈ es-TAH (stress on the second syllable)
sujo ≈ SOO-zhu (the j sounds like the s in measure)
vou ≈ voh (like English vo in vote, but shorter)
lavar ≈ la-VAR (final r often sounds like h: la-VAH)
agora ≈ ah-GO-rah (stress on GO)

In fast speech, you’ll often hear está reduced to tá: O prato tá sujo, vou lavar agora.

Is there a more informal way Brazilians might say this?

Yes. A very common informal version is:
O prato tá sujo, vou lavar agora.
Here tá is just the colloquial, shortened form of está and is extremely frequent in spoken Brazilian Portuguese.