Puella dicit cerasa dulciora esse quam persica.

Because after dicit (the girl says), Latin often uses an indirect statement construction.

Instead of saying:

• Puella dicit: Cerasa dulciora sunt quam persica.
  The girl says, “Cherries are sweeter than peaches.”

Latin can say:

• Puella dicit cerasa dulciora esse quam persica.
  literally, The girl says cherries to be sweeter than peaches

So:

• sunt = a finite verb, used in a direct statement
• esse = an infinitive, used in an indirect statement

This is one of the most important Latin sentence patterns to learn.

In this kind of sentence, Latin usually does not use a separate word meaning that.
Instead, the idea of that is built into the accusative + infinitive construction.

So English says:

• The girl says that cherries are sweeter than peaches.

But Latin says:

• Puella dicit cerasa dulciora esse quam persica.

The that is understood from the structure itself.

Because cerasa is a neuter plural form.

In Latin, many neuter plural nouns end in -a. So even though an English speaker may expect -a to be singular feminine, that is not always true.

Here:

• cerasum = a cherry or cherry fruit (singular neuter)
• cerasa = cherries (plural neuter)

So cerasa is plural, even though it ends in -a.

Yes. Persica is also a neuter plural form, meaning peaches.

Like cerasa, it ends in -a because it is neuter plural.

So:

• persicum = peach (singular)
• persica = peaches (plural)

Because it agrees with cerasa.

In Latin, adjectives must agree with the nouns they describe in:

• gender
• number
• case

Since cerasa is neuter plural, the comparative adjective must also be neuter plural:

• dulcior = sweeter (basic comparative form)
• dulciora = sweeter, agreeing with a neuter plural noun

So cerasa dulciora means sweeter cherries or, in this sentence, that cherries are sweeter.

It is the subject of the infinitive esse, so in an indirect statement it should be in the accusative.

That may sound confusing, because cerasa looks the same as the nominative plural. But with neuter plural nouns, the nominative plural and accusative plural are often identical.

So here:

• grammatical role in the indirect statement: subject of esse
• expected case: accusative
• actual form: cerasa, which looks the same as nominative plural

This is very common in Latin.

It is understood to be in the same case as the thing being compared.

Here the comparison is:

• cerasa dulciora ... quam persica
• cherries sweeter ... than peaches

Since cerasa is functioning as the subject of the infinitive and appears in the accusative form, persica is understood correspondingly after quam.

Because persica is neuter plural, its nominative and accusative forms are the same anyway, so the form does not visibly change.

Quam means than in comparisons.

So:

• dulciora quam persica = sweeter than peaches

A comparative adjective like dulciora is very often followed by quam.

This is the straightforward comparison pattern:

• X est maior quam Y = X is bigger than Y
• X est dulcior quam Y = X is sweeter than Y

Here it appears inside an indirect statement:

• cerasa dulciora esse quam persica = that cherries are sweeter than peaches

Because puella is the subject of the main verb dicit.

So the sentence has two layers:

1. Main clause:
   Puella dicit = The girl says

2. Indirect statement:
   cerasa dulciora esse quam persica = that cherries are sweeter than peaches

The subject of the main verb is nominative:

• puella = nominative singular

Yes. Latin word order is much freer than English word order because the endings show the grammatical relationships.

So this sentence could appear in other orders, for example:

• Puella cerasa dulciora quam persica esse dicit.
• Cerasa puella dicit dulciora esse quam persica.

These all mean essentially the same thing, though the emphasis may shift slightly.

The given order is perfectly normal, but Latin does not depend on rigid word order the way English does.

Because its subject, puella, is singular.

• puella = the girl
• dicit = she says / the girl says

If the subject were plural, the verb would also be plural:

• puellae dicunt = the girls say

Yes, but then it would usually be direct speech or a more independent clause.

For example:

• Puella dicit: Cerasa dulciora sunt quam persica.
  The girl says, “Cherries are sweeter than peaches.”

That is different in structure from:

• Puella dicit cerasa dulciora esse quam persica.
  The girl says that cherries are sweeter than peaches.

Both are good Latin, but the version with esse is the standard indirect statement pattern.

No. Puella is the subject of the whole sentence, because puella goes with the main verb dicit.

Cerasa is the subject only inside the indirect statement:

• main subject: puella
• subject of esse: cerasa

So a useful way to read the sentence is:

• Puella dicit = The girl says
• cerasa dulciora esse quam persica = that cherries are sweeter than peaches

The positive adjective is dulcis, dulce, meaning sweet.

Its comparative is dulcior, dulcius, meaning sweeter.

From that comparative stem, you get forms like:

• dulcior = masculine/feminine singular
• dulcius = neuter singular
• dulciora = neuter plural

So dulciora is the neuter plural comparative form agreeing with cerasa.

A very helpful literal breakdown is:

• Puella = the girl
• dicit = says
• cerasa = cherries
• dulciora = sweeter
• esse = to be
• quam persica = than peaches

Very literally:

• The girl says cherries to be sweeter than peaches.

Natural English:

• The girl says that cherries are sweeter than peaches.

That literal version is awkward in English, but it helps you see how Latin builds the sentence.