Você pode me emprestar sua caneta por um minuto?

Because você takes the third-person singular verb form in Portuguese.

So:

• você pode = you can
• tu podes = you can with tu in standard grammar

This is one of the first things English speakers have to get used to: você means you, but it does not use the same verb endings that English you would suggest.

In Brazil, você is very common. In some regions, people use tu, and in colloquial speech you may even hear mixed patterns like tu pode, but você pode is completely standard and very common in Brazilian Portuguese.

Because after poder (can / to be able to), the next verb normally stays in the infinitive.

So the structure is:

• você pode
  • emprestar

Just like:

• Você pode ajudar? = Can you help?
• Você pode esperar? = Can you wait?
• Você pode me emprestar...? = Can you lend me...?

This is similar to English can lend, can help, can wait, where the second verb also does not change much.

Here, me means to me.

So:

• me emprestar = lend to me

In Brazilian Portuguese, pode me emprestar is the most natural everyday order.

A few useful comparisons:

• Você pode me emprestar sua caneta? = normal Brazilian Portuguese
• Você pode emprestar-me sua caneta? = grammatical, but sounds more formal or more European Portuguese
• Me empresta sua caneta? = very common in informal speech

So me before the infinitive is a very common Brazilian pattern.

Emprestar means to lend.

So this sentence is literally:

• Can you lend me your pen for a minute?

English often uses borrow from the speaker’s point of view:

• Can I borrow your pen?

But Portuguese usually keeps the lender’s action here:

• Você pode me emprestar sua caneta...?

If you want the idea of borrow, Portuguese often uses expressions like pegar emprestado.

Sua is the possessive adjective meaning your here, so:

• sua caneta = your pen

It agrees with caneta, which is feminine:

• seu livro = your book
• sua caneta = your pen

So the form changes to match the thing possessed, not the person who owns it.

Yes. Seu / sua can sometimes mean:

• your
• his
• her

In this sentence, because you are directly talking to someone, sua caneta is naturally understood as your pen.

If Brazilian Portuguese speakers want to avoid ambiguity for his/her, they often use:

• a caneta dele = his pen
• a caneta dela = her pen

That is very common in Brazil.

In Brazilian Portuguese, possessives are often used with or without the definite article.

Both of these are natural:

• sua caneta
• a sua caneta

So:

• Você pode me emprestar sua caneta?
• Você pode me emprestar a sua caneta?

Both work.

Whether the article appears can depend on region, style, rhythm, and personal preference. In this sentence, leaving it out sounds perfectly normal.

Because por is commonly used for duration of time.

So:

• por um minuto = for a minute
• por duas horas = for two hours
• por alguns segundos = for a few seconds

By contrast, para usually has meanings like:

• destination
• purpose
• deadline
• recipient

So for a time span, por is the natural choice here.

Not always.

Very often, por um minuto just means for a moment or briefly, not necessarily exactly 60 seconds.

Just like in English, people are often not being mathematically precise.

Other common casual alternatives would be:

• por um instante = for a moment
• um minutinho = just a sec / a little minute
• rapidinho = really quickly

Yes.

You can say:

• Pode me emprestar sua caneta por um minuto?

That sounds very natural.

Portuguese often leaves out subject pronouns when the context makes the subject clear. In a direct request like this, it is usually obvious that you are talking to the other person.

Including você can make the sentence a little more explicit, but omitting it is very common.

Yes. It is a normal, polite way to ask.

If you want to sound a little softer or more formal, you could say:

• Você pode me emprestar sua caneta por um minuto, por favor?
• Você poderia me emprestar sua caneta por um minuto?

The version with poderia is a bit more like Could you... in English.

If you want something more casual, people also say:

• Me empresta sua caneta um minutinho?

So your original sentence is polite and completely usable.

A rough pronunciation guide would be:

vo-SEH POH-djee mee em-pres-TAR SOO-ah ka-NEH-tah por ũ mee-NOO-too?

A few pronunciation notes:

• você sounds roughly like vo-SEH
• pode is often closer to POH-djee in many Brazilian accents
• me is usually an unstressed mee
• caneta is ka-NEH-ta
• um has a nasal sound
• r in emprestar is typically a light tap in many Brazilian pronunciations

In casual speech, você is often reduced to cê:

• Cê pode me emprestar sua caneta por um minuto?

That is very common in spoken Brazilian Portuguese.