Pater dicit se mox domum rediturum esse.

Because after dicit, Latin often uses an indirect statement construction rather than a clause introduced by that.

In English, we say:

• Father says that he will return home soon.

In Latin, that becomes:

• Pater dicit se mox domum rediturum esse.

In an indirect statement, the subject of the reported statement goes into the accusative, so se is the accusative form of the reflexive pronoun, meaning himself.

So se here means that he himself—and because the main subject is pater, it refers back to father.

This sentence uses the accusative-and-infinitive construction, often called indirect statement.

The pattern is:

• a verb of saying, thinking, knowing, perceiving, etc.
• followed by:
  • an accusative subject
  • an infinitive

So here:

• Pater dicit = Father says
• se = accusative subject of the reported statement
• rediturum esse = infinitive phrase meaning will return

Literally, the structure is something like:

• Father says himself to be about to return home soon

but natural English is:

• Father says that he will return home soon.

Because redire is the present infinitive, while rediturum esse is the future infinitive.

Latin uses different infinitives in indirect statement to show time relative to the main verb:

• present infinitive = happening at the same time
• perfect infinitive = happening before
• future infinitive = happening after

Since the meaning is he will return, Latin needs the future infinitive:

• rediturum esse = to be going to return / to return in the future

So:

• se redire would suggest that he is returning
• se rediturum esse means that he will return

It is made from two parts:

• rediturum = future active participle of redeo
• esse = infinitive of sum

So:

• rediturus, -a, -um = about to return / going to return
• rediturum esse = to be about to return, which in context means will return

Because the subject is se, referring to pater, the participle is masculine singular accusative:

• nominative masculine singular: rediturus
• accusative masculine singular: rediturum

If the subject were feminine, it would be redituram esse.

Because it agrees with se, which is the subject of the indirect statement, and se is accusative.

In Latin, adjectives and participles agree with the noun or pronoun they describe in:

• gender
• number
• case

Here:

• se = accusative singular
• rediturum must match it

Since se refers to pater, it is understood as:

• masculine
• singular
• accusative

So rediturum is masculine singular accusative as well.

Because se is a reflexive pronoun, and in this kind of sentence it normally refers back to the subject of the main clause.

Main clause:

• Pater dicit = Father says

Indirect statement:

• se ... rediturum esse = that he will return

Since se is reflexive, it points back to pater. So the meaning is:

• Father says that he himself will return soon.

If Latin wanted to refer to some other man, not the father, it would normally use another pronoun, not se.

Because domum is one of the common Latin expressions for motion toward home, and it does not need a preposition.

So:

• domum = homeward / to home / home

This is a special idiomatic use. Compare:

• eo domum = I am going home
• redeo domum = I return home

Latin often treats domus in special ways because it is such a common word.

Mox means soon.

It is an adverb, so it modifies the verb idea will return. Latin word order is flexible, so mox can appear in different places without changing the basic meaning.

Here:

• se mox domum rediturum esse

means that he will return home soon.

The placement before domum rediturum esse is natural, but Latin could move it around for emphasis.

Latin relies much more on endings than on word order to show grammar.

English depends heavily on position:

• Father says that he will return home soon

Latin can arrange the words more freely because the forms already show their roles:

• pater = subject of dicit
• se = accusative subject of the indirect statement
• rediturum esse = future infinitive
• domum = destination
• mox = adverb

So the Latin order is not random, but it is much freer than English. Often the infinitive is placed toward the end, and that feels very natural in Latin prose.

Not if the meaning is that father himself will return.

• se refers back to the subject of dicit, namely pater
• eum would usually refer to some other male person

So:

• Pater dicit se mox domum rediturum esse = Father says that he will return soon
• Pater dicit eum mox domum rediturum esse = Father says that he (someone else) will return soon

That distinction is one reason se is important.

Yes. That is the literal force of the future infinitive.

So word-for-word, the indirect statement is roughly:

• se ... rediturum esse = himself to be about to return

But in normal English, after says that, the best translation is usually:

• that he will return

So about to return helps you understand the Latin form, while will return is usually the most natural translation.

It comes from redeo, redire, redii/redivi, reditum, meaning to go back, return.

The future active participle is:

• rediturus, reditura, rediturum

In the sentence you see the accusative masculine singular form:

• rediturum

because it agrees with se, referring to pater.

In classical prose, esse is normally expressed in a form like this:

• se rediturum esse

In some poetry or later Latin, forms of esse may sometimes be omitted, but for a learner, you should expect and use the full classical form with esse included.

So in standard prose, this sentence is exactly what you would expect.