Το πλήθος έξω ακούει το χειροκρότημα του κοινού.

Because πλήθος is a collective noun. It means something like crowd, multitude, or large number, but grammatically it is singular and neuter.

So Greek uses:

• το πλήθος = the crowd
• ακούει = hears, is hearing

Even though a crowd contains many people, the grammar treats it as one group.

For the same reason: the subject is το πλήθος, which is grammatically singular. So the verb must also be 3rd person singular.

• ακούει = he/she/it hears or is hearing

If the subject were actually plural, such as οι άνθρωποι (the people), then you would use a plural verb:

• Οι άνθρωποι ακούνε... = The people hear...

Here έξω means outside. It is being used as an adverb.

In this sentence, it describes where the crowd is:

• Το πλήθος έξω = the crowd outside

Greek often uses έξω this way without adding a preposition, especially when the meaning is already clear from context.

Depending on context, Greek could also use a fuller expression like:

• το πλήθος που είναι έξω = the crowd that is outside
• το έξω πλήθος is not the normal way to say it here

So το πλήθος έξω is a natural compact structure.

Yes, but χειροκρότημα is often used as a singular noun meaning applause or clapping as one whole event/sound.

So:

• το χειροκρότημα = the applause

Greek can also use the plural:

• τα χειροκροτήματα = applauses, rounds of applause, bursts of clapping

But in this sentence, the singular is completely natural because it refers to the applause as one thing being heard.

Because του κοινού is in the genitive case.

The phrase is:

• το χειροκρότημα του κοινού

Literally, this means:

• the applause of the audience

So του κοινού shows who the applause belongs to or comes from.

A quick comparison:

• το κοινό = the audience (nominative/accusative)
• του κοινού = of the audience (genitive)

This is a very common Greek pattern:

• το βιβλίο του μαθητή = the student’s book
• η φωνή της γυναίκας = the woman’s voice

Yes. κοινός / κοινή / κοινό is originally an adjective meaning common, shared, or public.

But το κοινό is also a very common noun meaning:

• the public
• the audience

So in this sentence:

• του κοινού = of the audience

This kind of adjective-to-noun use is very common in Greek.

Because Greek uses the definite article very often, more often than English does.

In this sentence:

• το πλήθος = the crowd
• το χειροκρότημα = the applause
• του κοινού = of the audience

Each noun naturally takes its article because each one refers to a specific thing in the situation.

This may feel repetitive to an English speaker, but it is normal Greek style.

It is in the accusative case, because it is the direct object of the verb ακούει.

The sentence structure is:

• Το πλήθος = subject
• έξω = adverb
• ακούει = verb
• το χειροκρότημα του κοινού = direct object

So the crowd is the one hearing, and the applause is what is being heard.

It is present tense, 3rd person singular, from the verb ακούω = to hear.

So ακούει can mean:

• hears
• is hearing

Which English translation fits best depends on context. Greek present tense can cover both a simple present and an ongoing present meaning.

Greek word order is more flexible than English word order.

This sentence has a neutral order:

• Το πλήθος έξω ακούει το χειροκρότημα του κοινού.

But Greek could move elements around for emphasis, for example:

• Έξω το πλήθος ακούει το χειροκρότημα του κοινού.
• Το χειροκρότημα του κοινού ακούει το πλήθος έξω.
  This is less neutral and would sound more marked or literary.

So the original version is a straightforward, natural way to say it.

Sometimes Greek adverbs can create that kind of ambiguity, but here the most natural reading is that έξω describes the crowd:

• the crowd outside hears the applause

If you wanted to clearly say that the hearing happens outside, Greek would usually make that clearer from context or phrasing. In this sentence, learners will usually understand έξω as attached to το πλήθος.

A more expanded version would be:

• Το πλήθος που είναι έξω ακούει το χειροκρότημα του κοινού.

This means:

• The crowd that is outside hears the audience’s applause.

The original sentence is shorter and more natural in many contexts, but the expanded version can help learners see the structure more clearly.