A não ser que a internet caia, eu vou enviar o resumo e a conclusão ainda hoje.

A não ser que means unless.

It introduces an exception or condition:

• A não ser que a internet caia... = Unless the internet goes down...

It is a fixed expression, so it is best learned as a chunk. In Portuguese, it is normally followed by the subjunctive, which is why you see caia and not cai.

Because a não ser que triggers the subjunctive mood.

The verb cair in the present subjunctive for ela / você / a internet is:

• que eu caia
• que você / ele / ela caia
• que nós caiamos
• que vocês / eles / elas caiam

So:

• A internet cai = The internet goes down / The internet falls
  
  • this is indicative, used for a fact or regular event
• A não ser que a internet caia = Unless the internet goes down
  
  • this is subjunctive, used after that expression of condition/uncertainty

Because the noun internet is treated as feminine in Portuguese, so it takes a:

• a internet
• a internet está lenta
• a internet caiu

This is something you mainly just memorize with the noun.

Yes, cair literally means to fall, but it is also commonly used for systems, connections, or services that stop working.

So in Brazilian Portuguese:

• A internet caiu = The internet went down
• A ligação caiu = The call dropped
• O sistema caiu = The system went down

This is very natural usage.

Eu vou enviar is the very common near future structure in spoken and everyday Portuguese.

It literally looks like I am going to send, but very often it simply means I will send.

Compare:

• Eu vou enviar o resumo hoje. = very natural, common
• Enviarei o resumo hoje. = also correct, but more formal or written

Brazilian Portuguese often prefers ir + infinitive in normal conversation.

Yes. Portuguese often drops subject pronouns when the verb already makes the subject clear.

So both are fine:

• A não ser que a internet caia, eu vou enviar o resumo e a conclusão ainda hoje.
• A não ser que a internet caia, vou enviar o resumo e a conclusão ainda hoje.

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

Portuguese uses definite articles more often than English.

Here:

• o resumo = the summary
• a conclusão = the conclusion

If the context already makes it clear which summary and which conclusion you mean, the definite article is natural.

English might sometimes omit articles in similar situations, but Portuguese usually does not.

They are two different nouns:

• resumo = summary
• conclusão = conclusion

For example, in a paper or report:

• resumo is the condensed overview
• conclusão is the final section or final takeaway

Both are masculine/feminine as follows:

• o resumo
• a conclusão

Ainda hoje means still today or later today, depending on context.

In this sentence, it means the speaker intends to send it before the end of today.

Compare:

• hoje = today
• ainda hoje = still today / before today ends

It adds a sense of not waiting until tomorrow.

The comma separates the conditional clause from the main clause:

• A não ser que a internet caia,
• eu vou enviar o resumo e a conclusão ainda hoje.

This is similar to English:

• Unless the internet goes down, I’ll send the summary and the conclusion later today.

The comma is especially natural when the conditional part comes first.

Yes. You can put the main clause first and the unless clause after it:

• Eu vou enviar o resumo e a conclusão ainda hoje, a não ser que a internet caia.

This means the same thing. The version with a não ser que... first may sound a little more organized or formal, but both are correct.

Yes. Literally, a não ser que is built from ser and historically has the idea of if it is not the case that..., but in modern usage you should treat it as a fixed expression meaning unless.

So learners usually do better memorizing:

• a não ser que + subjunctive

rather than trying to translate each word separately every time.

Yes, and it changes the perspective slightly.

• A não ser que a internet caia = unless the internet goes down
• Se a internet não cair = if the internet doesn’t go down

These are very close in meaning here.

Grammar difference:

• a não ser que takes the subjunctive: caia
• se in this kind of real future condition usually takes the future subjunctive: cair

So:

• Se a internet não cair, vou enviar...
• A não ser que a internet caia, vou enviar...

Both are natural.

Because after a não ser que, Portuguese requires a conjugated subjunctive verb, not the infinitive.

So:

• correct: a não ser que a internet caia
• incorrect: a não ser que a internet cair

Cair is the infinitive, while caia is the present subjunctive form needed here.

The original sentence is already natural. In everyday speech, a Brazilian might also say:

• A não ser que a internet caia, vou mandar o resumo e a conclusão ainda hoje.

Here, mandar may sound a little more conversational than enviar, especially in informal contexts.

But both are good:

• enviar = a bit more neutral/formal
• mandar = often more everyday and conversational

Conclusão is pronounced approximately like kon-kloo-ZOWN in Brazilian Portuguese, though the final part is nasal.

Important points:

• the stress is on the last syllable: -são
• ão is a very common nasal ending in Portuguese
• it does not sound exactly like English ow

Other examples with the same ending:

• informação
• situação
• construção

This nasal sound takes practice, but it is extremely common in Portuguese.