Sina Pedro at Maria ang mga tagapakinig.

Sina is the plural personal marker used with more than one person's name.

• si Pedro = Pedro
• sina Pedro at Maria = Pedro and Maria

So because there are two named people, Pedro and Maria, Filipino uses sina, not si.

This is a very common Filipino sentence pattern for equational sentences, where one noun phrase is identified as another noun phrase.

In Sina Pedro at Maria ang mga tagapakinig:

• sina Pedro at Maria = the predicate
• ang mga tagapakinig = the topic/subject

Filipino often puts the predicate first and the ang-marked phrase second. So even though English would normally say Pedro and Maria are the listeners, Filipino often structures it as Pedro and Maria — the listeners.

There is no separate word for are here.

Filipino often leaves out the verb to be in simple identification sentences. So:

• Sina Pedro at Maria ang mga tagapakinig
  naturally means Pedro and Maria are the listeners

This is normal and very common in Filipino.

Ang marks a common-noun phrase as the topic/subject of the sentence.

Here, ang mga tagapakinig means the listeners.
So ang is not exactly the same as English the, but in many simple examples it can look similar.

A helpful way to think of it here is:

• ang mga tagapakinig = the listeners / the audience members

Mga marks plurality.

So:

• tagapakinig = listener
• mga tagapakinig = listeners

Even though Pedro and Maria already tells you there are two people, mga is still used because it makes tagapakinig explicitly plural.

Tagapakinig is a noun meaning listener or audience member.

In this sentence:

• mga tagapakinig = listeners / audience members

So the whole sentence identifies Pedro and Maria as the people who are listening.

English usually puts the subject first:

• Pedro and Maria are the listeners.

Filipino very often puts the predicate first in this kind of sentence:

• Sina Pedro at Maria ang mga tagapakinig.

So the order is different, but the meaning is the same. This is one of the things English speakers often need time to get used to in Filipino.

Yes. That is also correct.

• Sina Pedro at Maria ang mga tagapakinig
• Ang mga tagapakinig ay sina Pedro at Maria

Both mean the same thing. The second version is a more explicit subject-first pattern, with ay linking the two parts. The first version is very natural and common in everyday Filipino.

No. In this sentence, sina already marks the whole coordinated name phrase.

So the normal form is:

• sina Pedro at Maria

not usually:

• sina Pedro at si Maria

Once sina is used, it covers both names together.

Yes, depending on context.

Literally, mga tagapakinig means the listeners. But in natural English, that can sometimes be expressed as the audience if the situation is a talk, program, performance, or similar event.

So both of these may fit, depending on context:

• Pedro and Maria are the listeners
• Pedro and Maria are the audience members