Pater dicit talem rumorem saepe falsum esse.

Because Latin uses a special construction after verbs of saying, thinking, knowing, hearing, and so on: the accusative-and-infinitive construction, often called indirect statement.

So after dicit (says), Latin does not normally use a finite verb with that. Instead, it puts:

• the subject of the reported statement in the accusative
• the verb of the reported statement in the infinitive

So in:

Pater dicit talem rumorem saepe falsum esse

the reported statement is basically:

Such a rumor is often false.

But once it becomes indirect after dicit, rumor becomes rumorem and est becomes esse.

For the same reason: this is an indirect statement.

English usually says:

• Father says that such a rumor is often false.

Latin usually says:

• Father says such a rumor to be often false.

That sounds unnatural in English, but it is the normal Latin pattern. So:

• est = is in a direct statement
• esse = to be in an indirect statement

A direct version would be:

Talis rumor saepe falsus est.
= Such a rumor is often false.

After dicit, that becomes:

Pater dicit talem rumorem saepe falsum esse.

Because falsum agrees with rumorem.

In the indirect statement, rumorem is accusative singular masculine, so the predicate adjective describing it must also be accusative singular masculine:

• rumorem = accusative singular masculine
• falsum = accusative singular masculine

Even though in English we say the rumor is false, in Latin the adjective still agrees with the noun inside the accusative-and-infinitive construction.

Compare:

• Direct: Talis rumor saepe falsus est.
• Indirect: Pater dicit talem rumorem saepe falsum esse.

So falsus changes to falsum because rumor changes to rumorem.

Talem is the accusative singular form of talis, meaning such or of that sort.

Since it modifies rumorem, it must match it in:

• gender: masculine
• number: singular
• case: accusative

So:

• nominative: talis rumor = such a rumor
• accusative: talem rumorem = such a rumor in the accusative

Again, the accusative is required because this is indirect statement after dicit.

Because Latin usually does not use a conjunction meaning that after verbs like say, think, know, hear, and similar verbs when introducing a statement.

Instead, Latin prefers the accusative + infinitive construction.

So English says:

• Father says that such a rumor is often false.

Latin says:

• Pater dicit talem rumorem saepe falsum esse.

There are other ways Latin can introduce clauses, but with verbs of saying and thinking, the accusative-and-infinitive pattern is extremely common and standard.

Latin word order is much more flexible than English word order, because case endings show the grammatical relationships.

A very literal order here is:

• Pater = father
• dicit = says
• talem rumorem = such a rumor
• saepe = often
• falsum esse = to be false

So the sentence is effectively:

Father says such a rumor often to be false.

In smoother English:

Father says that such a rumor is often false.

The word order is perfectly normal Latin. The main thing is to recognize the structure:

• main clause: Pater dicit
• indirect statement: talem rumorem saepe falsum esse

Saepe means often, and here it modifies the whole idea of being false.

So the sense is:

• such a rumor is often false

not:

• there is often such a rumor

In other words, saepe goes with falsum esse: the rumor is false frequently or in many cases.

The direct statement would be:

Talis rumor saepe falsus est.
= Such a rumor is often false.

Then after Pater dicit:

• talis becomes talem
• rumor becomes rumorem
• falsus becomes falsum
• est becomes esse

So:

Pater dicit talem rumorem saepe falsum esse.

This is a very useful way to understand indirect statement: first imagine the direct sentence, then convert it.

Because Latin has no articles.

So pater can mean:

• father
• the father
• a father
• sometimes even my father, depending on context

Likewise, talem rumorem does not literally contain a separate word for a.

Latin expresses definiteness and indefiniteness mostly through context, not through articles.

Its basic meaning is such, of such a kind, or that sort of.

So talem rumorem can be understood as:

• such a rumor
• a rumor of that sort
• that kind of rumor

The exact English wording depends on context, but such a rumor is usually the most natural translation.

Yes. Pater is nominative singular, so it is the subject of the main verb dicit.

So the sentence divides like this:

• Pater dicit = Father says
• talem rumorem saepe falsum esse = that such a rumor is often false

It helps to keep the two layers separate:

1. the main statement: Father says
2. the reported statement: such a rumor is often false

Yes, but this is the standard and most natural way after dicit.

Latin could sometimes use different constructions in other contexts, but with a verb of saying, the accusative-and-infinitive is the normal textbook pattern.

So for a learner, the important lesson is:

After dico, expect:

• an accusative subject
• an infinitive verb

That is exactly what you have here:

• talem rumorem = accusative subject of the indirect statement
• esse = infinitive verb of the indirect statement