Desculpa, eu não vi a sua mensagem ontem.

Desculpa here is a very common, informal way to say sorry or excuse me in Brazilian Portuguese.

In this sentence, it works almost like a standalone apology:

• Desculpa, eu não vi... = Sorry, I didn’t see...

A few related forms:

• Desculpa → informal, common in everyday speech
• Desculpe → more formal or polite
• Me desculpa / Me desculpe → forgive me / sorry

So Desculpa is very natural in casual Brazilian Portuguese.

Here, desculpa is functioning as a verb form used as an apology.

That said, desculpa can also be a noun meaning excuse:

• Isso não é desculpa. = That’s not an excuse.

But in Desculpa, eu não vi a sua mensagem ontem, it means Sorry.

The comma separates Desculpa from the main statement.

It reflects how the sentence is spoken:

• Desculpa, ... = Sorry, ...

So the structure is:

• apology first: Desculpa
• explanation after: eu não vi a sua mensagem ontem

This comma is very natural in writing.

Yes, eu can be omitted.

Portuguese often drops subject pronouns when the verb form already makes the subject clear:

• (Eu) não vi a sua mensagem ontem.

Both are correct:

• Eu não vi a sua mensagem ontem.
• Não vi a sua mensagem ontem.

Including eu can add a little emphasis or clarity, but it is not required.

In Portuguese, não usually comes directly before the conjugated verb.

So:

• não vi = didn’t see

This is the normal pattern:

• Eu não sei. = I don’t know.
• Ela não chegou. = She didn’t arrive.
• Nós não queremos isso. = We don’t want that.

So eu não vi is the standard word order for negation.

Vi is the preterite form of ver (to see) for eu.

• ver = to see
• eu vi = I saw
• eu vejo = I see
• eu via = I used to see / I was seeing

In this sentence, the speaker is talking about one completed event in the past: they did not see the message yesterday. That is why vi is used.

So:

• eu não vi = I didn’t see
• not eu não vejo = I don’t see
• not eu não via = I wasn’t seeing / I didn’t use to see

Yes. The verb ver is irregular.

Some useful forms:

• eu vejo = I see
• eu vi = I saw
• eu vou ver = I’m going to see

Because ver is common, it is worth memorizing its past form:

• eu vi
• você/ele/ela viu
• nós vimos
• eles/elas viram

In Brazilian Portuguese, it is very common to use the definite article before a possessive:

• a sua mensagem
• o meu carro
• a nossa casa

So both of these are possible:

• a sua mensagem
• sua mensagem

In Brazil, a sua mensagem often sounds especially natural. The article is very common, though in many contexts it can be omitted.

It can, but not always.

Mensagem means message in a broad sense:

• text message
• WhatsApp message
• direct message
• written message in general

So the exact meaning depends on context. In modern everyday Brazilian Portuguese, many people would naturally understand it as some kind of phone/app message if that fits the situation.

Yes, teu is possible, but sua is much more common in much of Brazil because você is more common than tu.

Common pairings:

• você → seu / sua
• tu → teu / tua

So:

• a sua mensagem matches você
• a tua mensagem matches tu

In Brazil, even in places where tu is used, people may still use verb forms and possessives in mixed ways. But for most learners of Brazilian Portuguese, sua mensagem is a very safe and natural choice.

Ontem means yesterday, and time expressions often appear at the end of the sentence in Portuguese.

So this is very natural:

• Eu não vi a sua mensagem ontem.

But Portuguese is flexible, and you could also say:

• Ontem eu não vi a sua mensagem.
• Eu ontem não vi a sua mensagem. (possible, though less neutral)

Putting ontem at the end is one of the most natural everyday choices.

Yes — and that sounds very natural.

Compare:

• Desculpa, eu não vi a sua mensagem ontem.
• Desculpa, não vi sua mensagem ontem.

The shorter version is very common in speech and texting. Portuguese often drops:

• the subject pronoun (eu)
• sometimes the article before the possessive (a)

Both versions are correct.

It is informal to neutral, and very natural in everyday Brazilian Portuguese.

Why:

• Desculpa is informal
• the rest of the sentence is standard and neutral

If you wanted a more formal version, you might say:

• Desculpe, eu não vi a sua mensagem ontem.

So the original sentence is perfect for casual conversation, messaging, friends, coworkers in a relaxed context, and everyday use.

Yes. That is also correct and natural.

Compare the two:

• Desculpa, eu não vi a sua mensagem ontem.
• Desculpa por não ter visto a sua mensagem ontem.

The first one is more direct and conversational:

• Sorry, I didn’t see your message yesterday.

The second one is slightly more structured:

• Sorry for not having seen your message yesterday.

In normal conversation, the first version is usually more common and simpler.

In Brazilian Portuguese, não is nasalized. A rough approximation for English speakers is something like nowng, but that is only approximate.

Important points:

• the ã is nasal
• the final o is not pronounced like a full English oh

So try to produce a nasal sound rather than a plain vowel. Listening and repeating native audio helps a lot with this word, because não is extremely common.

Yes, you can, and it sounds natural too.

Compare:

• Desculpa, eu não vi a sua mensagem ontem.
• Eu não vi a sua mensagem ontem, desculpa.

The first starts with the apology. The second gives the explanation first and adds the apology afterward.

Both are common. The choice depends on tone and emphasis.