Pater filium exheredat.

Because pater is in the nominative singular, which is the case normally used for the subject.

• pater = father as the doer of the action
• filium = the one receiving the action
• exheredat = disinherits

So the grammar tells you that pater is the one doing the disinheriting.

Because filium is in the accusative singular, the case used for a direct object.

Compare:

• filius = son as a subject
• filium = son as an object

In this sentence, the son is the one being disinherited, so Latin uses filium.

The ending -at tells you that the verb is:

• third person
• singular
• present tense
• active
• indicative

So exheredat means he disinherits or she disinherits. Here, because the subject is pater, it means the father disinherits.

Latin does not have articles like English the and a/an.

So:

• pater can mean father, a father, or the father
• filium can mean son, a son, or the son

English has to choose one when translating, but Latin does not need to say it.

Because English usually sounds more natural with his son in this context. Latin does not explicitly include a possessive word here.

So literally, the Latin is just:

• Father disinherits son

But in ordinary sense, a father would normally disinherit his own son, so English often makes that explicit.

If Latin wanted to be completely explicit, it could say something like filium suum.

You would usually look them up as:

• pater, patris = father
• filius, filii = son
• exheredo, exheredare, exheredavi, exheredatus = disinherit

For nouns, Latin dictionaries usually give the nominative and genitive forms.
For verbs, they usually give the principal parts.

• pater is a third-declension noun
• filius is a second-declension noun

That is why their forms change differently:

• pater → subject form
• patrem → object form

but

• filius → subject form
• filium → object form

Learning declensions helps you recognize these patterns quickly.

It is not wildly irregular, but it does have a stem change that learners need to notice:

• nominative: pater
• genitive: patris

So the stem is really patr-, even though the nominative looks slightly different.

This is very common in third-declension nouns.

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

So all of these could mean the same basic thing:

• Pater filium exheredat
• Filium pater exheredat
• Exheredat pater filium

The endings still show that:

• pater is the subject
• filium is the object

Different word orders can change emphasis, but not the basic meaning.

Yes. It comes from exheredo, exheredare, which is a first-conjugation verb.

That is why the present-tense third-person singular form ends in -at:

• amo → amat
• laudo → laudat
• exheredo → exheredat

So the form fits a very common pattern.

A simple classroom pronunciation would be:

• pater = PAH-ter
• filium = FIH-lee-um
• exheredat = eks-heh-RAY-dat

A rough full pronunciation would be:

PAH-ter FIH-lee-um eks-heh-RAY-dat

The exact pronunciation can vary depending on whether you are using classical or ecclesiastical Latin, but that gives a good basic guide.

By itself, filium just means son in the accusative singular. Grammatically, it does not have to mean his own son.

However, in normal real-world sense, when the subject is father, readers usually understand son as the father's own son unless context suggests otherwise.

So:

• grammar: simply son
• usual sense in context: his son

A very literal breakdown is:

• pater = father
• filium = son as direct object
• exheredat = disinherits

So the most literal English order would be:

Father son disinherits

Then you turn that into natural English:

The father disinherits his son or A father disinherits a son, depending on context.