Pater dicit primam stationem prope flumen esse.

Because after a verb like dicit (says), Latin often uses an indirect statement.

Instead of saying:

• Pater dicit quod prima statio prope flumen est = Father says that the first stop is near the river

classical Latin much more often says:

• Pater dicit primam stationem prope flumen esse

In this construction:

• the verb of the reported statement goes into the infinitive: esse = to be
• the subject of that reported statement goes into the accusative: primam stationem

So esse is exactly what we expect here.

This is one of the most important Latin patterns: the accusative-and-infinitive construction.

In English we say:

• Father says that the first station is near the river.

In Latin, the reported clause becomes:

• primam stationem ... esse

Here:

• stationem is grammatically the subject of esse
• but in indirect statement, that subject appears in the accusative case

So even though stationem is logically the thing that is near the river, Latin puts it in the accusative because it is inside reported speech after dicit.

Because both words are inside the indirect statement and must match the construction.

The basic nominative phrase would be:

• prima statio = the first station

But in indirect statement, the subject becomes accusative:

• primam stationem

Also, the adjective primam must agree with stationem in:

• gender: feminine
• number: singular
• case: accusative

So:

• nominative: prima statio
• accusative: primam stationem

Primam is:

• feminine
• singular
• accusative

It is the adjective primus, prima, primum (first) agreeing with stationem.

Since stationem is accusative singular feminine, primam must be too. Latin adjectives match the nouns they describe.

Because prope is a preposition that takes the accusative.

So:

• prope flumen = near the river

Even though English speakers often associate location with the ablative in Latin, not every expression of place uses the ablative. Some prepositions simply govern the accusative, and prope is one of them.

So flumen here is accusative singular.

With a neuter noun like flumen, the nominative and accusative singular are the same in form:

• nominative singular: flumen
• accusative singular: flumen

So you tell by the syntax, not by the ending alone.

Here it must be accusative because:

• it follows prope
• prope takes the accusative

Latin often does not use a separate word for that after verbs of saying, thinking, knowing, hearing, and so on.

English says:

• Father says that...

Latin usually just starts the indirect statement:

• Pater dicit primam stationem prope flumen esse

So the idea of that is built into the whole accusative-and-infinitive construction. There is no need for a separate word.

The main verb is dicit = says.

Everything after that—primam stationem prope flumen esse—is the content of what is being said.

So the sentence breaks down like this:

• Pater = father
• dicit = says
• primam stationem prope flumen esse = the first station to be near the river / that the first station is near the river

Pater is the subject only of dicit.

The subject of esse is primam stationem, even though it is in the accusative because of indirect statement.

So the structure is:

• Pater → says
• primam stationem → is near the river

This is a very common point of confusion for English speakers, because English does not mark this distinction as clearly.

Yes, that is a useful literal translation for understanding the grammar.

But in normal English, we would usually say:

• Father says that the first station is near the river.

The more literal version helps you see the Latin structure:

• dicit = says
• stationem ... esse = the station to be / that the station is

So literal translation is helpful for study, even if it sounds unnatural in English.

The word order is meaningful, but it is not as rigid as English word order.

Here we have:

• Pater = subject first
• dicit = main verb early
• primam stationem = the subject of the indirect statement
• prope flumen = phrase describing location
• esse = infinitive at the end

Putting esse at the end is very normal in Latin. Latin often places the verb of an infinitive clause at the end.

So this order is natural, but Latin could rearrange parts of the indirect statement for emphasis more easily than English can.

You would look it up as statio, stationis.

In this sentence, stationem is the accusative singular form.

A learner should get used to recognizing that the form in the sentence may not be the dictionary form. Here:

• dictionary form: statio
• sentence form: stationem

Yes, but the accusative-and-infinitive is the normal classical construction after dicit.

A learner may sometimes meet later or less classical patterns using quod or similar words, roughly like English that. But for standard Latin prose, after a verb of saying, the expected pattern is:

• [accusative subject] + [infinitive]

So in this sentence, primam stationem ... esse is exactly the standard construction you want to learn.